'Marita' was the German and Italian strategic seizure of the Greek mainland and many of the Greek islands (6/30 April 1941).

As presaged by Adolf Hitler’s Führerweisung Nr 20 of 13 December 1940, the invasion of Greece eventually resulted from events in Yugoslavia, particularly the 27 March 1941 overthrow, in a military coup d'état inspired by the 18 year old King Petar II, of the Yugoslav administration headed by the regent, Prince Pavle. Two days earlier this latter had signed the Tripartite Pact, thereby tying Yugoslavia to the Axis cause, in an attempt to stave off Italian, Hungarian and Romanian pressures for annexations of Yugoslav territory. Hitler was so incensed by the overturning of this agreement, however, that on 27 March he ordered the rapid preparation of the 'Unternehmen 25' campaign that would bring Yugoslavia firmly under the German heel. At the same time he decided that the simultaneous conquest of Greece would secure the whole of Germany’s southern flank before the launch of 'Barbarossa', deny the use of the country to the British for the forward basing of bombers which might undertake attacks on the Romanian oilfields and installations at Ploieşti that were of strategic importance to Germany, and also rescue the Italian forces locked hopelessly in a fruitless campaign in Albania and north-western Greece.

The whole of the Balkan campaign involved a first phase, in which Greek forces and units of the RAF successfully fought off the Italian forces that had invaded Greece in October 1940 in 'Emergenza G', then a second phase in which the poorly equipped, poorly trained, politically divided and badly led Yugoslav forces fought unsuccessfully from 6 April 1941 to beat off a concerted offensive by Axis ground and air forces in 'Unternehmen 25', and a third phase which also began on 6 April 1941 and in which Greek, British and commonwealth forces unsuccessfully resisted the 'Marita' invasion of Greece.

After Italy had invaded and occupied Albania in April 1939, Benito Mussolini, the Italian Fascist leader, assured the rest of the world that Italy had no designs on Greece. The British and French governments nevertheless made an immediate pledge to maintain Greek and Romanian independence. Germany and Italy reacted to this by signing the 'Pact of Steel', which strengthened the Rome-Berlin Axis agreement of 1936. When Italy declared war on France and the UK on 10 June 1940, Mussolini still maintained that he had no interest in Greece, but on 28 October, after accusing Greece of allowing British forces to violate its neutrality, sent troops across the border from Albania. Though its forces were dangerously stretched at home, and by the battle for the Mediterranean, the UK immediately dispatched five RAF squadrons to Greece and established an inter-service mission.

The Italian offensive, which lacked both the strength and the commitment to accomplish its planned task, collapsed in the face of determined Greek resistance, and by 14 November the Greeks had launched a counter-offensive to drive the Italians back into Albania. The Greek commander-in-chief, Antistrátegos Alexandros Papagos, was sure that the Italians in Albania would soon be reinforced and, in an effort to secure victory before this could happen, drove his forces forward: on 6 December the Greeks had reached Sarandë on the coast and by 10 January 1941 had captured Kleisura on the Vjosë river, while British bombers, despite the adverse weather conditions, struck at Italian port facilities and lines of communication, and also supported the Greek advance on Valona.

Meanwhile, during November 1940 the Germans had begun their own preparations for an invasion of Greece through Romania and Bulgaria, not to aid the Italians but to protect the Romanian oilfields on which they were dependent for much of their fuel, and to secure the southern flank of their planned 'Barbarossa' invasion of the USSR. First to appear in the area were units of the Luftwaffe, and in January 1941 a build-up of German ground forces started in Romania, which after the fall of France had repudiated an Anglo-French pledge and aligned itself with Germany. The presence of Luftwaffe units in Bulgaria, and other factors suggestive of Germany’s Balkan intentions, became known to the British by means of 'Ultra' and other more conventional intelligence sources. By the second week in February, after Germany had failed to secure a halt in the Greco-Italian war by diplomatic means, it became abundantly clear that Greece was to be attacked on a second front.

During January 1941 the Greeks had come to believe that the British desired to embroil Greece in a long conflict with Germany and the British suspected the Greeks were considering a separate peace with the Italians, and as an initial result a British offer of ground forces and a Greek request for British matériel were both refused.

At the time of the Axis invasion, Greece was thus already at war with Italy following the Italian 'Emergenza G' invasion of 28 October 1940, and as a result, when 'Marita' began on 6 April, the main strength of the Greek army was deployed in the Albanian frontier region. In 'Marita' the German troops invaded through Bulgaria, creating a second front. Greece had already received a small though inadequate reinforcement of British and commonwealth forces delivered in anticipation of the German attack, but no more help was sent after the German invasion had started. The Greek army therefore found itself outnumbered in its effort to defend against both Italian and German troops, and as a result in the far north-east the defences along the Greco/Bulgarian frontier did not receive adequate troop reinforcements and was quickly overrun by the Germans, who then outflanked the Greek forces in the Albanian borders, forcing their surrender.

The British-led forces were powerless to halt the German onslaught and forced to retreat to the south toward the ports from which they could be evacuated across the Mediterranean to Egypt. The German forces reached Athens, the Greek capital, on 27 April and the south coast of mainland Greece three days later, capturing some 7,000 men of the British and commonwealth forces. and ending 'Marita' with a decisive victory. The conquest of Greece was completed with the capture of Crete one month later in 'Merkur'. Following its capitulation, Greece was occupied by German, Italian and Bulgarian military forces.

Adolf Hitler later blamed the failure of the 'Barbarossa' invasion of the USSR, whose start had been delayed by six weeks by 'Marita', on Mussolini’s failed conquest of Greece and therefore his need to come to the support of his Tripartite Pact ally. Although largely specious as a reason for the failure of 'Barbarossa', it cannot be denied that 'Marita' nevertheless had serious consequences for the Axis war effort in the North African theatre, in which the British retention of Malta was a decisive factor, and it has rightly been emphasised that Hitler’s decision not to undertake the 'Herkules' airborne assault on Malta was a strategic error resulting directly from the very heavy losses of the German airborne arm in 'Merkur'.

On the outbreak of World War II in 1939, Strátegos Ioannis Metaxas, the right-wing dictator of Greece, attempted to maintain a Greek neutrality. However, Greece was subject to increasing pressure from Italy, culminating with the sinking, but the Italian submarine Delfino of the Greek cruiser Elli on 15 August 1940. Benito Mussolini, the Italian Fascist leader, was irritated by the fact that Adolf Hitler, the German Nazi leader, had not consulted him on Germany’s war policy and wished to establish Italy’s nationalist policy by the launch of independent operations. Mussolini hoped to match the German military successes of 'Weiss' (i) against Poland, 'Weserübung' against Denmark and Norway, and 'Sichelschnitt' against the Netherlands, Belgium and France by the Italian seizure of Greece, which he regarded as an easy target. On 15 October 1940, Mussolini and his senior advisers finalised their decision, and in the early hours of 28 October Emanuele Grazzi, the Italian ambassador, presented Metaxas with a three-hour ultimatum to give free passage to Italian troops for the occupation of unspecified 'strategic locations' in Greece. Metaxas rejected the ultimatum, but even before the ultimatum had expired Italian troops had marched into north-western Greece through Albania, which was already under Italian occupation.

The main Italian thrust was directed toward the region of Epiros in north-western Greece. The first clash between Italian and Greek forces was the Battle of Elaia-Kalamas, in which the Italians failed to break the Greek defensive line and compelled to halt. Within three weeks the Greek army launched a successful counter-offensive in which it marched into Albanian territory, capturing significant cities such as Korytsa (Korçë) in the north and Agioi Saranta (Sarandë) in the south. Neither a change in Italian command nor the arrival of substantial reinforcements improved the Italian situation.

After weeks of inconclusive winter warfare, the Italians launched another major offensive on the centre of the front on 9 March 1941, but despite the Italians' overall superiority this failed. After a single week and 12,000 casualties, Mussolini terminated the offensive.

During this six-month campaign, the Greek army made territorial gains by destroying Italian salients, but Greece lacked any substantial armaments industry, and both its equipment and ammunition supplies had come to rely increasingly on stocks captured by the British from the Italians in North Africa. Moreover, to mass sufficient numbers of men for the Albanian front, the Greek command had been compelled to thin its forces in eastern Macedonia and western Thrace. Although the Greek command knew it lacked the strength to protect the whole of Greece’s land frontiers, it nonetheless decided to support its success on the Albania front despite the risk of a German and/or Bulgarian attack across the Greco/Bulgarian border.

Hitler intervened on 4 November 1940, four days after the first British troops had arrived on the islands of Crete and Lemnos in the south and north respectively of the Aegean Sea: although Greece had been neutral until the Italian invasion, the British troops delivered onto Greek national territory could now be construed as having created the possibility of a new front on Germany’s southern flank. Hitler therefore ordered the preparation of a campaign to take northern Greece from land and air bases in Bulgaria and air bases in Romania within the context of his master plan to deprive the British of Mediterranean bases. On 12 November, the Oberkommando der Wehrmacht issued a directive scheduling the simultaneous launch of operations against Gibraltar and Greece in January 1941. In December 1940, however, German ambitions in the Mediterranean were of necessity radically revised after the dictator of Spain, General Francisco Franco y Bahamonde, specifically rejected any German assault on Gibraltar across Spanish territory, and after this German offensive operations in southern Europe were limited to the Greek campaign.

On 13 December 1940 the Oberkommando der Wehrmacht issued a new directive outlining the Greek campaign under the codename 'Marita'. In this, German forces were to take and hold the north coast of the Aegean Sea by March 1941, thereby giving German overland access to the Mediterranean Sea via the Aegean Sea, and to seize the entire Greek mainland if this proved necessary. Then, during a hasty meeting of Hitler’s staff after the unexpected coup d'état of 27 March by the Yugoslav king and air force officers against the Yugoslav government, which had only two days earlier signed the Tripartite Pact, orders for the new 'Unternehmen 25' campaign against Yugoslavia were drafted, and changes to the plans for the campaign against Greece agreed. On 6 April, both Greece and Yugoslavia were to be attacked.

The other main participant in the campaign which was to follow was the UK and its commonwealth. The UK had committed itself to the assistance of Greece by a declaration of 1939, which stated that in the event of a threat to Greek or Romanian independence 'His Majesty’s Government would feel themselves bound at once to lend the Greek or Romanian Government… all the support in their power.' The first concrete evidence that the UK felt itself bound by this declaration was the deployment of Royal Air Force squadrons, under the command of Air Commodore J. d’Albiac, which started to arrive in November 1940. With the final approval of the Greek government, British forces had in fact already been dispatched to Crete on 31 October to guard Souda Bay, a strategically important naval anchorage on the island’s north coast, and this allowed the Greek government to redeploy Hypostrátegos Georgios Papastergiou’s 5^th Cretan Division to the mainland.

On 17 November 1940, Metaxas proposed to the British government a joint offensive in the Balkans with Greek strongholds in southern Albania as its operational bases. The British were reluctant to discuss Metaxas’s proposal as they wished to undertake a defensive war if required, and also because the additional formations which the Greek plan would require would seriously jeopardise operations in North Africa such as the 'Compass' offensive which was currently being planned.

Churchill believed it was vital for the UK to take every measure possible to support Greece. On 8 January 1941, he stated that 'there was no other course open to us but to make certain that we had spared no effort to help the Greeks who had shown themselves so worthy.'

During a meeting of British and Greek political and military and political leaders in Athens on 13 January 1941, Papagos, the commander-in-chief of the Greek army, asked the UK for the delivery of nine divisions and air power to match. The British responded that all they could offer was the immediate dispatch of a token force of less than divisional strength. This offer was rejected by the Greeks, who feared that the arrival of so small a force might well trigger a German offensive without providing the Greeks any meaningful assistance. The Greeks decided to request a greater degree of British aid if and when the movement of German troops to the south across the Danube, from Romania into Bulgaria, became evident.

Only a little more than one month later, the British decided that the time was ripe for a reappraisal of their situation, largely because Prime Minister Winston Churchill wished to create a Balkan front comprising Yugoslavia, Greece and Turkey, and instructed the foreign secretary, Anthony Eden, and the Chief of the Imperial General Staff, General Sir John Dill, to reopen talks with the Greek government. At meeting attended by Eden and the Greek leadership, including King Georgios II, prime minister Alexandros Koryzis (successor to Metaxas, who had died on 29 January) and Papagos, which took place in Athens on 22 February, Eden told the Greek government that the British would send troops to help defend their country on condition that the Greeks agreed to abandon Thrace and Macedonia to the Axis forces by withdrawing westward to a new defensive position, the Aliákmon Line, which ran from the mouth of the Aliákmon river, through Veroia and Edessa, to the Yugoslav frontier just to the east of the Monastir gap. The British believed that the Greeks had agreed to this plan, but when Eden returned to Athens on 2 March, having failed to achieve anything in drawing Turkey into the war on the Allied side and with Yugoslavia still sitting on the fence, he found that Papagos, whose understanding had been that forming the Aliákmon Line had been conditional on Yugoslavia’s reply to Eden’s request for support, had not even started the withdrawal.

Even so, late in February the British decided that it was time for the creation of a British and commonwealth expeditionary force would for rapid despatch to Greece as it was now known that German troops had been massing in Romania. On 1 March, these German forces started to move to the south into Bulgaria, and at the same time the Bulgarian army was mobilising and starting to occupy positions along the Greco/Bulgarian frontier.

On 5 March 'Lustre' began for the movement of troops, weapon and supplies from Egypt to Greece, and 26 troopships arrived at the port of Piraeus. Events were now starting to develop rapidly, and on 3 April, in the course of a meeting between British, Greek and Yugoslav military representatives, the last undertook to block the valley of Struma river, flowing to the south through western Bulgaria into western Macedonia and into the Aegean Sea, in the event of a German offensive across their territory. Papagos stressed the importance of a joint Greco/Yugoslav offensive against the Italians immediately the Germans launched their offensive.

On 9 March the Italians launched their second offensive against the Greeks on the Albanian front but, despite now having 28 divisions at their disposal, were again unable to effect any breakthrough. During this month Yugoslavia was under constant pressure from Germany to join the Tripartite Pact, and eventually did so on 25 March, and it was this which precipitated an anti-Nazi coup d'état. Having agreed, but only with great reluctance, to withdraw the Greek forces from Thrace at the suggestion of the British, Papagos now reversed his decision. This left 3.5 Greek divisions manning the Metaxas Line, extending from the mouth of the Nestos river to the southern side of the Beles mountains in the area to the west of the Rupel pass, to protect Thessaloníki while another three divisions manned the Aliákmon Line with the British and commonwealth 'W' Force commanded by Lieutenant General Sir Henry Maitland Wilson, who commanded the British and commonwealth forces in Greece.

By 24 April more than 62,000 British, Australian, New Zealand, Palestinian and Cypriot troops had arrived in Greece, these comprising Major General Iven G. Mackay’s Australian 6^th Division, Major General Bernard C. Freyberg’s New Zealand 2^nd Division, Brigadier H. V. S. Charrington’s British 1^st Armoured Brigade and a number of supporting British artillery units, which became 'W' Force after Wilson, its commander, with Lieutenant General Thomas Blamey, commander of the two-division Australian I Corps, as his second-in-command. Although initially earmarked for deployment to Greece, Generał brygady Stanisław Kopański’s Polish Independent Carpathian Rifle Brigade and Major General John D. Lavarack’s Australian 7^th Division were retained in Egypt because of the first and very successful German thrust into Cyrenaica and toward Egypt.

d’Albiac commanded the British air forces in Greece. The total of RAF squadrons was now seven, and though aided by two squadrons of Egypt-based bombers for night operations, two of these were operating with the Greeks on the Albanian front, and what remained was no match for the 650 or more first-line aircraft of General Wolfram Freiherr von Richthofen’s VIII Fliegerkorps of Generaloberst Alexander Löhr’s Luftflotte IV.

To enter the northern part of Greece from Bulgaria, the German forces faced significant terrain problems inasmuch as they had to cross the Rhodope mountains, which possess only a few river valleys and mountain passes suitable for the transit of major military units. Two invasion routes were located in the area to the west of Kyustendil, and a third along the Bulgarian/Yugoslav frontier down the Struma river valley. The Greek border fortifications had been carefully created to extract the maximum benefit from the terrain and a formidable defence system covered the few available roads. The Struma and Nestos rivers cut across the mountain range along the Greco/Bulgarian frontier and both of their valleys were protected by strong fortifications, as part of the larger Metaxas Line. This was a system of concrete pillboxes and field fortifications, constructed just along the Greek side of the Bulgarian border in the late 1930s and schemed on principles similar to those of the Maginot Line in France. Its strength rested primarily in the inaccessibility of the intermediate terrain leading up to the defence positions.

However, despite increasing evidence that German troops were moving in large numbers over the Danube river into Bulgaria during the early spring of 1941, the Greek and the combined British and commonwealth forces in Greece were unable to establish a coherent front because of command disagreements. The Greeks wanted adamantly to fight their battle along the Metaxas Line, a line of strong fortifications built during the 1930s along the Bulgarian border from the mouth of the Nestos river on the north coast of the Aegean Sea, north-west up the Metaxas river and then west across the Struma river and south of the Beles mountains almost to Dojran on the Greco/Yugoslav border. This course of action was posited on the idea of exploiting the region’s naturally difficult terrain, enhanced in defensive capability by the man-made fortifications, while protecting the strategically important port of Thessaloníki. But the Greek plan disregarded the fact that the forces and equipment available were adequate only for a token resistance, and that the Metaxas Line was vulnerable to a flanking attack past its western end, through the Vardar river valley and past Dojran, if the neutrality of Yugoslavia was violated. Obsessed with its fears of Bulgarian aggression against its long and comparatively shallow regions between the Aegean Sea and Bulgaria, and being on traditionally good terms with the Yugoslavs, the Greeks had left the Yugoslav border region largely without man-improved defences.

Greece’s mountainous terrain favoured a defensive strategy and the high ranges of the Rhodope, Epiros, Pindos and Olympos mountains offered many defensive opportunities. However, air power was required to protect defending ground forces from entrapment in the many defiles if their positions were turned. Although an invading force from Albania could be stopped by a relatively small number of troops positioned in the high Pindos mountains, the north-eastern part of Greece was difficult to defend against an attack from the north.

After a conference in Athens during March, the British believed that they would combine with Greek forces to occupy the Aliákmon Line, which extended from a point on the Greco/Yugoslav border to the north-west of Edessa, past Edessa, along the north-eastern face of the Vermion mountains to Véroia and finally along the lower part of the Aliákmon river to its estuary on the Aegean Sea just to the west of the estuary of the Vardar river, known in Greece as the Axios river. The advantage of Wilson’s position was that it required fewer forces, and that more time would therefore be available for the preparation of the line against Axis forces invading from Bulgaria. But any concentration of the defence on the Aliákmon Line meant nearly the entire northern part of Greece would have to be abandoned to its fate, and this was unacceptable to the Greeks for obvious political and psychological reasons. Moreover, the left flank of the Aliákmon Line was susceptible to any flanking movement by the Germans through the Monastir gap in Yugoslavia to debouch into Greece to the west of Lake Vegorrítis behind the north-western end of the Aliákmon Line.

But Papagos was still awaiting clarification from the Yugoslav government and later proposed that the allied forces hold the Metaxas Line (now to the Greek population as much a symbol of national security as the Maginot line had been to the French up to May 1940, yet with no greater justification) and not withdraw divisions from the Albanian front. Papagos’s case was that to do so would be seen as a concession to the Italians. However, Papagos’s plan left strategically important port of Thessaloníki practically undefended and the 'Faggot' movement of British troops, weapons and supplies to the city remained dangerous. Papagos’s answer to British concerns was that he proposed to take advantage of the area’s terrain and prepare fortifications, while also protecting Thessaloníki.

Dill saw Papagos’s attitude as narrow-minded yet defeatist, and argued that his plan ignored the fact that Greek troops and artillery were capable of only token resistance to a German invasion. The British believed that the Greek rivalry with Bulgaria, the Metaxas Line having been designed and constructed specifically against the eventuality of war with Bulgaria, as well as their traditional amity with the Yugoslavs left the nation’s north-western border largely undefended. Despite their awareness that the line was likely to collapse in the event of a German thrust down the valleys of the Struma and Axios rivers, the British little option but to accede to the plan of the Greek command. On 4 March, Dill accepted the plans for the Metaxas Line, and on 7 March the agreement was ratified by the British war cabinet.

The result of this disagreement was the creation of two (and therefore weaker) defence positions rather than one strong position, one along the Metaxas Line held by Bakopoulos’s Eastern Macedonia Army Section, and one along the Aliákmon Line held largely by British and commonwealth forces. Predictably, both positions were easily overrun by the Germans.

Overall command was still to be vested in Papagos, and the Greek and British commands agreed to fight a delaying action in the north-east. The British did not move their troops as Wilson believed them to be too weak to protect such a broad front. Instead, he ordered 'W' Force to take position some 40 miles (65 km) to the south-west of the Axios river, across the Aliákmon Line, with the primary objectives of maintaining contact with the Greek army in Albania and denying any German offensive access to central Greece. The twin objectives had the advantage of requiring a smaller force than other options, and also provided greater time for preparation, though they also meant the abandonment of almost all of northern Greece, which was unacceptable to the Greeks for political and psychological reasons. Moreover, the line’s left flank was vulnerable to being outflanked by a German advance through the Monastir gap in southern Yugoslavia. However, the rapid disintegration of the Yugoslav army and a German thrust into the rear of the Vermion position were not expected.

The German strategy was based on the use of the now well-proved Blitzkrieg method which had proved itself during the German campaign in north-western Europe. The efficacy of the method was confirmed once more during the 'Unternehmen 25' invasion of Yugoslavia. Thus the German command combined armour, artillery and infantry under an air umbrella which provided total cover and also served as 'flying artillery' for the armoured forces roaming ahead of the slower-moving infantry and its horse-drawn artillery.

The German strategic aim was to use the XL Corps (mot.), freed by the lack of any significant opposition in Yugoslavia, to strike to the south between the Pindos mountains and Kozani to secure the complete division of the Greek forces in north-western and north-eastern Greece, while at the same time isolating the Central Macedonia Army Section and Eastern Macedonia Army Section from each other and from the rest of the country. These isolated groups could then be crushed individually with the aid of the VIII Fliegerkorps.

The initial objective was Thessaloníki, followed by Athens and the port of Piraeus. The loss of the last and the seizure of the isthmus of Corinth would fatally compromise any possibility of the withdrawal and evacuation of the British and Greek forces.

From north-west to south-east, the German force tasked with the main assault on Greece (Thrace and Macedonia) was Generalfeldmarschall Wilhelm List’s 12^th Army 1. The 12^th Army attacking from Bulgaria was to be supplemented on its left in the Monastir gap by elements of another of its formations, General Georg Stumme’s XL Corps (mot.) (Generalleutnant Alfred Ritter von Hubicki’s 9^th Panzerdivision, Generalleutnant Bruno Bieler’s 73^rd Division and SS-Obergruppenführer und General der Waffen-SS Joseph Dietrich’s brigade-sized Infanterieregiment (mot.) 'Leibstandarte SS Adolf Hitler') after it had first seized Yugoslav Macedonia and taken Skopje before wheeling south into the Monastir gap.

List’s last and indeed largest subordinate formation was Generaloberst Ewald von Kleist’s 1^st Panzergruppe (otherwise the Panzergruppe 'von Kleist'), whose two corps were in fact wholly committed to 'Unternehmen 25' and therefore played no part in 'Marita'.

In the west, Generale d’Armata Italo Garibaldi’s 9^th Army and Generale d’Armata Carlo Geloso’s 11^th Army were to advance from Albania into north-western Greece.

General Vladimir J. Cukavac’s Yugoslav 5^th Army had responsibility for the defence of the south-eastern border region between Kriva Palanka and the Greco/Yugoslav frontier, but the Yugoslav troops were not fully mobilised and lacked adequate equipment and weapons.

Following the entry of German forces into Bulgaria, the majority of the Greek troops were evacuated from western Thrace. By this time, the Greek forces defending the Greco/Bulgarian frontier totalled about 65,100 men, only about half of them combat-capable, of what British and Germans sources generally describe as the 2^nd Army although no such formation existed, while the rest of the Greek forces, the 15 or more divisions often erroneously known as the 1^st Army by British and German sources, was committed in Albania.

The forces available to face the expected German attack in Macedonia were mostly newly formed divisions manned by reservists and lacking heavy weapons and equipment. As noted above, the Greek high command did not agree with the British as to the deployment of its forces, being unwilling to abandon all of northern Greece in favour of the shorter line between the Vermion mountains and Aliákmon river favoured by the British, so the Greek forces in Macedonia were divided in two major groupings, which fought separate battles.

Antistrátegos Konstantinos Bakopoulos’s Eastern Macedonia Army Section covered the pre-war fortifications of the Metaxas Line between Mt Beles and the Nestos river with Hypostrátegos Christos Zoiopoulos’s 7^th Division (26^th, 71^st and 92^nd Regiments), Hypostrátegos Konstantinos Papakonstantinou’s 14^th Division, Hypostrátegos Leonidas Stergiopoulos’s 18^th Division, Hypostrátegos Nikolaos Lioumbas’s 19^th Mechanised Division (191^st, 192^nd and 193^rd Regiments), Syntagmatárches Anastasios Kalisis' Nestos Brigade, the Krousia Detachment and Hypostrátegos Ioannis Zisis’s Evros Brigade detached as a covering force for western Thrace, and the 21 fortresses of the Metaxas Line.

Also allocated directly to the defence of Metaxas Line by Yugoslavia was Lieutenant General Dragutin Zivanovic’s 20^th 'Bregalnička' Division (23^rd, 28^th and 49^th Regiments as well as the 20^th Artillery Regiment), which was part of the 3^rd Territorial Army and intended to prevent the 2^nd Panzerdivision from outflanking the entire Greek position by crossing into Greece from Yugoslavia.

Antistrátegos Ioannis Kotoulas’s Central Macedonia Army Section was assigned on 28 March to the 'W' Force in holding the line between the Vermion mountains and the Aliákmon Line with Syntagmatarches G. Karambatos’s 12^th Division (35^th and 80^th Regiments, the Dodecanese Regiment, the X Frontier Sector and the 20^th Mountain Artillery Regiment), and Hypostrátegos Christos Karassos’s 20^th Division (82^nd, 84h, 86^th and 87^th Regiments).

The rest of 'W' Force, which was only just settling into its positions as the German invasion began, comprised Australian, New Zealand and British elements in the form of Mackay’s Australian 6^th Division (Brigadier Arthur S. Allen’s 16^th Brigade, Brigadier Stanley G. Savige’s 17^th Brigade and Brigadier George A. Vasey’s 19^th Brigade, Freyberg’s New Zealand 2^nd Division (Brigadier E. Puttick’s 4^th Brigade, Brigadier J. Hargest’s 5^th Brigade and Brigadier H. E. Barrowclough’s 6^th Brigade), and Charrington’s British 1^st Armoured Brigade.

Wilson had his headquarters to the north-west of Larissa. The New Zealand 2^nd Division took position to the north of Mt Olympos, while the Australian 6^th Division blocked the valley of the Aliákmon river up to the Vermion range. The RAF continued to operate from airfields in central and southern Greece, but was short of aircraft, and many of those which had been made available were obsolescent as only a very few modern warplanes could be diverted to the theatre. The 'W' Force was almost completely motorised, but its equipment was better suited to desert warfare than to operations over steep Greek mountain roads. The 'W' Force was short of tanks and anti-aircraft guns, and its lines of communication across the Mediterranean Sea were very exposed as each convoy had to pass close to Axis-held islands in the Aegean Sea, which was dominated on the surface by Admiral Sir Andrew Cunningham’s Mediterranean Fleet but in the air was largely dominated by German and Italian warplanes. The 'W' Force’s logistical problems were aggravated by the limited availability of shipping and relatively small capacity of Greek ports.

The German overall plan drew heavily on the army’s experience in 'Sichelschnitt' and 'Rot' (iii) in the French campaign, and the strategy was centred on the creation of a diversion through the campaign in Albania, thus stripping the Greek army of troops for the defence of its frontiers with Yugoslavia and Bulgaria. Then, by driving armoured punches through the weakest links of the allied chain of defences, the Germans believed that they would be able to penetrate deep in Greece without any need for substantial armour backing an infantry advance. Once southern Yugoslavia had been overrun by German armour in 'Unternehmen 25', the Metaxas Line could readily be outflanked by mobile forces thrusting to the south from Yugoslavia. Thus, possession of Monastir and its gap would allow the Aliákmon Line to be outflanked round its north-western end, while seizure of the Axios river valley woulds open the way to Thessaloníki

The anti-German coup d'état after Yugoslavia’s entry into the Tripartite Pact demanded a major alteration of the core plan and confronted the 12^th Army with a number of difficult problems. According to the Oberkommando der Wehrmacht’s directive of 28 March, the 12^th Army was to create a mobile task force to attack toward Belgrade, the Yugoslav capital, down the Morava river valley after entered south-eastern Yugoslavia to take Nis. With only nine days left before the German forces' final deployment, every moment was important as each redeployment needed time. By the evening of 5 April, the forces which would enter southern Yugoslavia and northern Greece had been assembled.

It was at dawn on 6 April that the German forces began the 'Marita' invasion of Greece. The XL Corps (mot.) moved off at 05.30 to advance to the south-west cross the extreme south-east of Yugoslavia, take Skopje on the Vardar river and then wheel to the south-east and enter the Monastir gap. The corps advanced across the Bulgarian frontier in two columns at separate points. By the evening of 8 April, the 73^rd Division had taken Prilep, severing an important railway line linking Belgrade and Thessaloníki, thereby isolating Yugoslavia from its allies. On the evening of 9 April, Stumme deployed his forces to the north of Monastir in readiness for the planned attack toward Flórina. This position threatened to encircle the Greek forces in Albania and 'W' Force in the area of Flórina, Edessa and Katerini. While small security detachments covered Stumme’s rear against the possibility of a surprise attack from central Yugoslavia, elements of the 9^th Panzerdivision pushed to the west to link with the Italians on the Albanian border.

The 2^nd Panzerdivision of the XVIII Gebirgskorps entered Yugoslavia on the morning of 6 April and advanced to the west through the Struma river valley. The division met little resistance, but was delayed by the needs to clear roads and also to overcome demolitions, mines and mud, but was nevertheless able to reach its first-day objective, the town of Strumica. On 7 April, the division beat off a Yugoslav counterattack against its northern flank, and on the following day drove its way across the mountains and overran the elements of the Greek 19^th Motorised Division located to the south of Lake Doiran. Despite encountering several varied delays along the mountain roads to the east of the Axios river, a German armoured advance guard despatched toward Thessaloníki entered the city by the morning of 9 April. The capture of Thessaloníki involved no fighting, and was followed by the surrender of the East Macedonia Army Section with effect from 13.00 on 10 April.

The Metaxas Line was held by the Eastern Macedonia Army Section’s 7^th, 14^th and 18^th Divisions, and extended about 106 miles (170 km) from the mouth of the Nestos river on the Aegean Sea just opposite Thásos island to the north-west up the river’s western side and then to the west on the Greek side of the frontier with Bulgaria as far as Mt Beles near the Yugoslav border. The fortifications were designed to be held by a garrison of more than 200,000 men, but the actual number had been reduced to 65,100 men to satisfy the manpower requirements of the Albanian front, so the line was only thinly defended. The Greek matériel resources for the defence of the Metaxas Line included 40 tankettes, 188 pieces of field artillery, 76 anti-tank guns and 30 anti-aircraft guns.

Eventually using almost the full available strength of the XVIII Gebirgskorps and XXX Corps, the Germans had to break the line to capture Thessaloníki, the most heavily populated city of northern Greece and possessing a port of strategic significance. The Battle of the Metaxas Line, which is known in Greece as the Battle of the Forts, began on 6 April with the commitment of two divisions and one infantry unit of the XVIII Gebirgskorps. The Greek resistance was initially strong, and on the first day of their attack the Germans made little progress in breaking the line, a German report at the end of the first day describing how the 5^th Gebirgsdivision in the Rupel pass despite despite the strongest possible air support (the 12^th Army could call on 650 aircraft) and sustained major losses. Of the 24 forts constituting the Metaxas Line, only two had fallen and then only after they had been destroyed rather than captured by direct assault.

Over the following days, the Germans deluged the remaining forts with artillery fire and the bombs of dive-bombers, and had to reinforce the 125^th Regiment. A 7,000-ft (2135-m) snow-covered pass, which was considered inaccessible by the Greeks, was successfully crossed by the 6^th Gebirgsdivision, which reached the railway line to Thessaloníki during the evening of 7 April. The 5^th Gebirgsdivision and reinforced 125^th Regiment next managed a very difficult opposed crossing of the Struma river, attacked along both banks and cleared a series of bunker position until they reached their objective on 7 April, though heavy casualties meant that they then had to be pulled back, albeit only temporarily. The 72^nd Division advanced from Nevrokop across the mountains, though its advance was delayed by a shortage of pack animals, medium artillery and mountain equipment, and it was only during the evening of 9 April that the division reached the area to the north-east of Sérres, the second largest town of central Macedonia, to the east of the Struma river and south-east of Lake Kerkini. Most of the forts of the Metaxas Line, such as Roupel, Echinos, Arpalouki, Paliouriones, Perithori, Karadag, Lisse and Istibey, managed to hold out until after the Germans had occupied Thessaloníki on 9 April, whereupon they surrendered under Bakopoulos’s orders. Even so, a number of smaller forts continued to fight for a few days more and were not taken until heavy artillery was used against them, and this provided the time for some of the retreating Greek troops to be evacuated by sea. Although eventually defeated, the defenders of the Metaxas Line had succeeded in delaying the German advance.

On the left of the German assault, the XXX Corps reached its designated objective on the evening of 8 April as the 164^th Division on the corps' right captured Xanthi. The 50^th Division on the corps' left pushed far beyond Komotini toward the Nestos river, and the two divisions linked on the following day.

On 9 April, the Greek forces defending the Metaxas Line capitulated unconditionally following the collapse of Greek resistance to the east of the Axios river. In an estimate of the situation on 9 April, List commented that as a result of the swift advance of the mobile forces, his 12^th Army was now well positioned to advance into central Greece by breaking the Greek build-up behind to the west of the Axios river. On the basis of this estimate, List successfully requested the transfer of Generalmajor Gustav Fehn’s 5^th Panzerdivision from the 1^st Panzergruppe to the XL Corps (mot.) as its availability would add weight to the German thrust through the Monastir gap. For the continuation of the campaign, List divided the 12^th Army into two as an eastern group under the command of the XVIII Gebirgskorps and a western group under the command of the XL Corps (mot.).

By the morning of 10 April, the XL Corps (mot.) had completed its preparations for the next phase of the offensive and advanced in the direction of Kozani, which lies in the southward bend of the Aliákmon river between Servia to the south-east and Flórina to the north-west. Against all German expectations, the Monastir gap had been left fully open and the Germans were quick to exploit this error. The first German contact with British and commonwealth troops in the Greek campaign took place to the north of Vevi at 11.00 on 10 April and this presaged the Battle of Vevi, otherwise known as the Battle of the Klidi Pass, during the next two days.

At this time, the strategic situation had resulted from the collapse of Yugoslav resistance to the 'Unternehmen 25' invasion, which exposed the left flank of the Vermion Line held by Greek and British forces. A new plan intended that British forces hold back the German forces in the western part of Macedonia, until non-motorised Greek infantry units had withdrawn on foot from Mt Vermion to Mt Siniatsiko, and a new defensive line had been created between Mt Olympus and the Aliákmon river. The XL Panzerkorps had advanced from Monastir on the morning of 10 April to seize Flórina, some 8 miles (13 km) to the south of the Greco/Yugoslav border, by way of the Monastir valley (or 'Monastir Gap'). The Infanterieregiment (mot.) 'Leibstandarte SS Adolf Hitler' and the 9^th Panzerdivision advanced farther to the south and occupied the town of Vevi. The 73^rd Division followed behind the Infanterieregiment (mot.) 'Leibstandarte SS Adolf Hitler' and attacked to the west with the object of widening the German breakthrough’s front. Encountering the Greek Cavalry Division in an action at Pisoderi Pass, the 73^rd Division failed to make progress.

A mixed Australian, British, New Zealand and Greek unit, 'Mackay' Force was hastily assembled with its headquarters at Perdika and the task of preventing 'a blitzkrieg down the Florina Valley'.

The Klidi pass links the towns of Vevi and Klidi to the south, and varies in width from 110 to 550 yards (100 to 500 m). The pass is a winding defile, with steep, rocky and treeless sides up to a height of 3,280 ft (1000 m). During April 1941, conditions at the top of the pass were extremely cold with rain turning to snow. These conditions made it difficult for all of the Allied troops to sleep or even to rest, and this was especially the case for the Australians and New Zealanders, who were exhausted after a long and sudden journey from North Africa, and were not experienced in or equipped for mountainous and wintry conditions.

'Mackay' Force was deployed in two sub-sectors: Greek forces round the town of Kelli, 6.25 miles (10 km) to the east of the pass and British forces at the pass itself. The British units occupying the pass comprised mostly Vasey’s Australian 19^th Brigade, which comprised the 2/4^th Battalion (less one company) and the 2/8^th Battalion, complemented by the British 9/King’s Royal Rifle Corps (also known as the 1^st Rangers). The infantry were supported by parts of the New Zealand 27^th (Machine Gun) Battalion, the Australian 2/1^st Anti-Tank Regiment, the British 2^nd Regiment, Royal Horse Artillery and other smaller elements of Australian and British artillery units. Vasey’s headquarters were located about 6.25 miles (10 km) to the south of Klidi.

Around the pass, Vasey’s three infantry battalions were spread across a frontage of some 10 miles (16 km) with the 2/8^th Battalion on the ridge to the east of the pass, the 1^st Rangers on a north-facing spur on pass’s western side, and the 2/4^th Battalion to the west of the Rangers on the 3,285-ft (1001-m) Golema Glava height. New Zealand machine gunners were distributed among the infantry, and the Australian and British artillery units were concentrated in the pass itself.

The Kelli sub-sector was covered by a Greek brigade-sized force, primarily the Dodecanese Regiment (three battalions with 3,500 men), which was reinforced by the Greek X Border Sector (500 men), single Greek batteries of mountain artillery, field artillery and anti-tank artillery, one engineer company and one machine gun company. The total strength of the Greek force, which was commanded by Syntagmatárches Sergios Aristotelis, was in the order of 5,000 men and 15 guns. The 3/Dodecanese Regiment was deployed on the right flank of the British units on Delinski Dol at a height of 3,935 ft (1200 m), followed by the 1/Dodecanese Regiment, 2/Dodecanese Regiment and the X Border Sector to the far right. Two 75-mm (2.95-in) guns were deployed in the anti-tank role between the 3/Dodecanese Regiment ans 1/Dodecanese Regiment to control the road through the village of Kelli.

Immediately to the west of the 'Mackay' Force and covering its left flank, across the Mala Reka ridge, were the 350 personnel of the 1/88^th Regiment of the 21^st Brigade, an element of the Greek Cavalry Division.

The German forces tasked to clear the way through the Klidi Pass were elements of the 9^th Panzerdivision and the Infanterieregiment (mot.) 'Leibstandarte SS Adolf Hitler'. During its swift progress through the southern part of Yugoslavia, the 9^th Panzerdivision had created its Vorausabteilung 'Apell' advance guard unit under the commander of the 9^th Schützenbrigade, Oberst Wilhelm von Apell, and this unit crossed into Greece together with the Infanterieregiment (mot.) 'Leibstandarte SS Adolf Hitler'. Support was provided by 12 150-mm (5.91-in) guns of the XL Corps (mot.)'s 2/37^th schwere Artillerieabteilung in the counter-battery role.

Located on the German right flank, the Vorausabteilung 'Apell' comprised the headquarters of the 9^th Schützenbrigade, 9^th Aufklärungsabteilung, 1/11^th Schützenregiment, 2/102^nd Artillerieregiment less its 6^th Batterie, one battery of the 86^th Flakabteilung, one company of the 50^th Panzerjägerabteilung and one company of the 86^th Pionierbataillon.

The Infanterieregiment (mot.) 'Leibstandarte SS Adolf Hitler' deployed with, on its right, the reinforced 1/Infanterieregiment (mot.) 'Leibstandarte SS Adolf Hitler', whose Kampfgruppe 'Witt' was to attack the Vevi pass frontally; and on the left the reinforced 3/Infanterieregiment (mot.) 'Leibstandarte SS Adolf Hitler', which was to attack the recognised decisive point of the battle and break through from Kelli toward Amyntaio. The 2/Infanterieregiment (mot.) 'Leibstandarte SS Adolf Hitler', less its 7^th Kompanie and 8^th Kompanie, was left in Flórina as a reserve while securing the area from the south and west. The reconnaissance group was initially ordered to link with the 2^nd Panzerdivision near Edessa, but then to pursue the Allies toward Sotir after the pass had been opened. To support the Kampfgruppe 'Witt', the 5/Infanterieregiment (mot.) 'Leibstandarte SS Adolf Hitler', which was the regiment’s 'heavy' battalion, detached 15 tracked self-propelled artillery pieces, comprising its battery of six 75-mm (2.95-in) Sturmgeschütz III assault guns and its company of nine 47-mm Panzerjäger I tank destroyer vehicles. The Infanterieregiment (mot.) 'Leibstandarte SS Adolf Hitler''s pioneer battalion was to wait behind the Kampfgruppe 'Witt' for orders. One light howitzer battery was available to provide direct support to the 3/Infanterieregiment (mot.) 'Leibstandarte SS Adolf Hitler', and a heavy howitzer battery to support the Kampgruppe 'Witt'. The Infanterieregiment (mot.) 'Leibstandarte SS Adolf Hitler''s SS Artilleriergiment, less one 88-mm (3.465-in) Flak battery, was to co-ordinate its actions with the Kampfgruppe 'Witt'.

SS-Sturmbannführer Fritz Witt commanded his eponymous battle group, which comprised the reinforced 1/Infanterieregiment (mot.) 'Leibstandarte SS Adolf Hitler', five infantry companies of the 2/Infanterieregiment (mot.) 'Leibstandarte SS Adolf Hitler', one machine gun company of the 2/Infanterieregiment (mot.) 'Leibstandarte SS Adolf Hitler', two 'light infantry weapon' platoons, one 'heavy infantry weapons' platoon, three anti-tank platoons, two pioneer platoons, one fight field howitzer troop, one 88-mm (3.465-in) Flak platoon, and a number of StuG III and PzJg I tracked vehicles.

Neither the Germans nor the Allies believed that armoured vehicles would be able to climb the extremely rocky slopes surrounding the pass, but this was to prove an erroneous assumption.

The dividing line between the Infanterieregiment (mot.) 'Leibstandarte SS Adolf Hitler' and the Vorausabteilung 'Apell' lay about 1.25 miles (2 km) to the west of and parallel with the road linking Niki, Vevi and Klidi. The assigned tasks were for the Infanterieregiment (mot.) 'Leibstandarte SS Adolf Hitler' to open the pass, and after this had been achieved, for the Vorausabteilung 'Apell' to move from the area of Flambouron toward Aetos and Xino Nero, and thus the rear of the Allied forces defending the pass.

At 00.00 on the night of 11/12 April, the Dodecanese Regiment detected German attempts to make reconnaissance patrols and probing attacks against Golema Glava, but were repelled after a two-hour engagement. The Germans made similar probing attacks at 14.00 against Delinski Dol, but were again unsuccessful.

The Infanterieregiment (mot.) 'Leibstandarte SS Adolf Hitler' did not probe the British part of the front until the afternoon of 11 April. This included an encounter with Australian artillery positions on the main road, and included the destruction of five German trucks and the loss of many men. By the morning of 12 April, fresh snow more than 12 in (0.305 m) deep lay on the sides of the hills, and many of the Australians and New Zealanders deployed there were suffering from frostbite and were thus unable to operate their weapons effectively. However, orders had now been issued for a withdrawal to the Aliákmon Line starting in that evening.

The outcome of these initial clashes with the Germans at Vevi were not encouraging for 'W' Force, and the rapid advance of the German armour into Thessaloníki and Prilep in southern Yugoslavia greatly disturbed Wilson, who was nonetheless able to time his moves nicely, in part as a result of the 'Ultra' intelligence he received: Wilson was informed of the intelligence’s origin, the first time a commander in the field had been made privy to the secret. The British commander was now faced with the prospect of being pinned by the invading Germans operating from Thessaloníki while being flanked by the formations of the XL Corps (mot.) descending through the Monastir gap behind his left flank. Orders had now been issued for an orderly withdrawal to the Aliákmon Line, however, to begin during the evening.

Between 08.30 and 09.00 on 12 April, the Germans began their main attack. Without any artillery preparation, the 1^st Kompanie of the Infanterieregiment (mot.) 'Leibstandarte SS Adolf Hitler', vanguard of the Kampfgruppe 'Witt' on its left flank, attacked the key Hill 997, which was occupied by a company of the 2/8^th Battalion. Hard close-quarter fighting developed, and by 11.00 the Germans had captured the hill after overrunning one Australian platoon, of which only six men survived. At 12.30 one company of the Kampfgruppe 'Witt' extended the attack toward Hill 917, which it had captured by 14.00 after overcoming strong resistance. The hill was defended by an Australian company in the extreme left of 2/8^th Battalion’s sector, near the point at which it adjoined the sector held by the 1^st Rangers.

According to the Australian official history, at 11.00 the 1^st Ranger, possibly in the belief that the 2/8^th Battalion was retreating, started to pull back. This opened the pass to the Germans, opened a gap between the 2/4^th and 2/8^th Battalions, severed communications between Vasey and the 2/8^th Battalion, and left Australian anti-tank guns without infantry protection. To the west of the battlefield, the Greek 21^st Brigade reported at 12.00 that it had lost contact with the 2/4^th Battalion. At 13.00, the Dodecanese Regiment reported that the 2/8^th Battalion was retreating, although the regiment had not yet in fact received any order to do so. The two companies of the 2/8^th Battalion on the western flank were compelled to retreat up the slopes. According to another Australian commentator, Vasey was informed of the 1^st Rangers' withdrawal by officers of other units but refused to believe it.

The Dodecanese Regiment’s line began to receive artillery fire at 14.30, concentrated mostly on Delinski Dol. In the west, the 21^st Brigade reported from 14.30 that groups of Australians were retreating to the south toward Xino Nero.

From 14.35 a number of assault guns and tank destroyer vehicles had arrived to support two companies of the Kampfgruppe 'Witt',

Following the earlier German successes, the 2^nd Kompanie of the Infanterieregiment (mot.) 'Leibstandarte SS Adolf Hitler' and a heavy machine gun platoon attacked to the west of the road, with the 3^rd Kompanie astride and to the east of the road, the 7^th Kompanie attacking from Hill 917 to the west of Klidi village, and the 1^st Kompanie from Hill 997 to the east of Klidi village. By 15.30, the first and second of these companies had taken Hill 1009 in the 1^st Rangers' sector after reducing the British machine gun positions with heavy weapons. At 16.00 the forces fighting the Kampfgruppe 'Witt' began to retreat after carrying out demolitions on the road. The Kampfgruppe 'Witt' attacked, and pioneers moved up it its wake to open a corridor in the Allied minefield, which made it possible for two assault guns to pass through. Simultaneously, the 3/Infanterieregiment (mot.) 'Leibstandarte SS Adolf Hitler' and Vorausabteilung 'Apell' began their attacks.

With German artillery fire on the Greek lines growing ever more intense, at 15.40 Mackay ordered the Dodecanese Regiment to effect an immediate retreat, which was to have been completed by 18.00, thereby bringing forward the withdrawal scheduled for 19.00. At 16.30, the Greek regiment began its withdrawal after destroying its artillery. When the regiment began its retreat, it reported that no British forces were to be seen in the Kirli Derven sector. The 3/Infanterieregiment (mot.) 'Leibstandarte SS Adolf Hitler' began its attack toward Kelli at 16.20.

At 16.00. in the western sector, the German attack was extended against the Greek 1/88^th Battalion, which began taking artillery and mortar fire. Between 16.30 and 18.00, a force reported by the Greeks as elements of the German vanguard concentrated against the battalion’s sector round Radosi hill, and quickly reached a close-assault distance under harassing fire from the Greeks.

The flanks of the 2/8^th Battalion had been exposed by the Greek and British withdrawals, and the battalion was soon under German machine gun fire from the east. Vasey saw that his men would be unable to make an orderly withdrawal, and at 17.00, he telephoned the commanding officer of the 2/4^th Battalion to order an immediate withdrawal. At 17.30 some 500 German infantry, supported by self-propelled guns, attacked in force along the width of the 2/8^th Battalion 's sector. The self-propelled guns effectively sealed the Allies' defeat at Vevi. The 2/8^th Battalion was forced into a chaotic retreat, with its constituent units becoming separated and officers ordering the abandonment even of light weapons to speed the withdrawal. Losses among the Australian infantry would have been much worse it were not for the 2/1^st Anti-Tank Regiment and the Royal Horse Artillery, which stood their ground in the centre until the Germans were only some 440 yards (400 m) distant.

German sources indicate that at 18.00 the 7^th Kompanie and 1^st Kompanie of the Infanterieregiment (mot.) 'Leibstandarte SS Adolf Hitler' captured the village of Klidi, after taking 82 prisoners. A little later the 3^rd Kompanie captured the exit of the rail tunnel, in the process taking another 250 New Zealand, British and Australian prisoners. Both Greek and German sources agree that the 3/Infanterieregiment (mot.) 'Leibstandarte SS Adolf Hitler' was in Kelli at 18.15, then occupied vacated Greek positions, and had reached Petra by 20.15. However, German sources suggest that Greek units were still fighting to the far east of the area at 20.00, when 40 Greek and 60 Australian prisoners were taken.

The early collapse of the Allied line in the Klidi pass allowed German forces to advance to the south of the pass before the Dodecanese Regiment had completed its withdrawal to the west. Its right-hand column, comprising the first and third battalions, as well as the regimental headquarters company, was attacked by six assault guns and nine tank destroyers at 18.00 to the west of Amyntaion, and the column was saved by the timely intervention of between 25 and 30 British tanks.

In the west, the positions of the 88^th Regiment were attacked at 18.30, and following a brief and unequal close-quarter clash the Germans overran the 88^th Regiment, which reeled back toward Aetos. According to Greek sources, an attempted counterattack was aborted when the 88^th Regiment’s commander was killed, but German sources mention repulsing a Greek attack against their right flank at 19.00.

Meanwhile, to the east, at 19.00 the 12^th Kompanie and 13^th Kompanie of the 3/Infanterieregiment (mot.) 'Leibstandarte SS Adolf Hitler' moved eastward over Hill 1202 (presumably Delinski Dol noted in Greek maps as Hill 1200), while the 14^th Kompanie advanced to the west of Lake Petron to take the village of Petres. The 2^nd Kompanie attacked astride the road, followed closely by the 3^rd Kompanie, while the 1^st Kompanie and 7^th Kompanie descended from the hills flanking the pass toward Sotir. At 21.00 operations stopped along a line extending from the east of Xino Nero almost to Sotir.

At 20.00, the remnants of the 88^th Regiment started to reach Aetos after suffering the loss of 11 men killed, 18 wounded and 96 captured (some of them wounded). The regiment then began to reorganise itself, although its numbers were sufficient to form only one company.

German sources also report that elements of the Vorausabteilung 'Apell' took Hill 966 (Seveskeravi hill) at 22.30 after hard fighting against Australian troops. However, the hill lay in the Greek sector and is not mentioned in the Australian or Greek official histories.

The 2/8^th Battalion had been effectively destroyed as a fighting unit for the rest of the Greek campaign. According to some accounts, at its fallback position of Rodona, the battalion could muster only 250 men, of whom only 50 had weapons. Although the 2/4^th Battalion had been spared the brunt of the German assault at Vevi, it had 70 personnel taken prisoner at a German roadblock during its retreat to Sotir. The Germans claimed 480 'English' prisoners at Vevi for its own loss of 37 dead, 95 wounded and two taken prisoner.

Although it had been defeated and suffered heavy losses, 'Mackay' Force had fought at Vevi an action which won two days for the retreat and regrouping of Allied forces to the south. Despite this, by the time the Allied resistance at Klidi collapsed, the Greek 12^th and 20^th Divisions had not yet completed their withdrawal, and subsequently found themselves having to defend their positions on Mt Siniatsiko line (the Kleisoura, Vlasti and Siatista passes) on very disadvantageous terms. The Dodecanese Regiment, the most combat-worthy of the 20^th Division’s units, was scattered during the westward withdrawal as a result of misunderstandings with the British, who had undertaken their movement in trucks as the regiment’s commander officer had opted not to make the scheduled rendezvous with his first and third battalions, and remained as the reserve of the 20^th Division for the remainder of the war. The bulk of the 20^th Division was still straggling westward towards Mt Siniatsiko when the brigade-sized Infanterieregiment (mot.) 'Leibstandarte SS Adolf Hitler' made contact with the main defensive line at Kleisoura in the evening on 13 April.

The 12^th Division, retreating through snowstorms over Mt Vermion, was still to the east of the road linking Flórina and Servia when 'Mackay' Force retreated from Klidi. Although the British 1^st Armoured Brigade fought delaying actions at Sotir and Proastio on 13 April, covering the withdrawal of the 12^th Division, the latter was eventually split by the German advance, losing three of its battalions which were cut off the main body and retreated southward toward Servia. When the 9^th Panzerdivision made contact with the Siatista defensive location at 13.30 on 14 April, only one battalion of the 82^nd Regiment was in position. As it awaited the German assault on Siatista pass on 15 April, the 12^th Division could muster an effective strength of only 1,000 men, all of whom were both demoralised and fatigued.

On the morning of 14 April, the spearheads of the 9^th Panzerdivision reached Kozani, and during the evening which followed the division established a bridgehead across the Aliákmon river, but an attempt to advance beyond this point was stopped by intense Allied fire.

As noted above, Wilson now had to face the prospect of his forces being pinned by Germans advancing to the west from Thessaloníki while being flanked by the XL Corps (mot.) moving to the south through the Monastir gap. On 13 April, he withdrew all British and commonwealth forces to the Aliákmon river and then to the narrow pass at Thermopylai. Wilson therefore ordered the British and commonwealth forces to fall back to a line which ran near Mt Olympus. This defence had three main elements, in the form of the Platamon tunnel area between Mt Olympus and the sea, the Olympus pass itself, and the Servia pass to the south-east. By channelling the German attack through these three defiles, the new line offered the limited defensive forces a checking capability far greater than they would have possessed in more open country. The defence of the Olympus and Servia passes was provided by Puttick’s New Zealand 4^th Brigade, Hargest’s New Zealand 5^th Brigade, and Allen’s Australian 16^th Brigade. For the next three days, the advance of the 9^th Panzerdivision was stalled by the determined resistance of these resolutely held positions.

A ruined castle dominated the ridge across which the coastal pass led to Platamon. During the night of 15 April, a German motorcycle battalion supported by a tank battalion attacked the ridge, but the Germans were repulsed by Colonel Macky’s New Zealand 21^st Battalion, which suffered heavy losses in the process. Later in the same day, a German armoured regiment arrived and fell on the battalion’s coastal and inland flanks, but the New Zealanders held once again. After being reinforced during the night of 15/16 April, the Germans assembled a tank battalion, an infantry battalion and a motorcycle battalion. The infantry attacked the New Zealanders' left-hand company at dawn, while the tanks attacked along the coast several hours later. Macky, who had lost touch with the company on his left, and had two companies farther down the hill being fired upon from the flank and the rear, gave the order to retire. The withdrawal was covered by the reserve company, which was on a ridge to the south of that pierced by the tunnel. Macky had intended to hold a new position about 1 mile (1.6 km) to the south of Platamon, but this was found to be impracticable, and the New Zealanders continued their retirement to the mouth of the Pinios gorge. The New Zealand battalion crossed the Pinios river and by a time just before the fall of night had reached the western exit of the Pinios gorge, suffering only light casualties.

It was here that Macky was informed that the gorge had to be denied to the Germans to 19 April even it this meant the destruction of his battalion. Macky ordered the sinking of a crossing barge at the western end of the gorge once his men were across and set up defences. The 21^st Battalion was reinforced by the Australian 2/2^nd Battalion and later by the 2/3^rd Battalion, the three antipodean battalions becoming known as 'Allen' Force. The 2/5^th and 2/11^th Battalions moved to the Elatia area, to the south-west of the gorge, and were ordered to hold the western exit for three or four days.

On 16 April, Wilson met Papagos at Lamia and informed him of his decision to withdraw to Thermopylai. Lieutenant General Sir Thomas Blamey, commanding the Australian Imperial Force, divided responsibility between Mackay and Freyberg during the leapfrogging move to Thermopylai. Mackay’s force was assigned the flanks of the New Zealand 2^nd Division as far to the south as an east/west line through Larissa, and to oversee the withdrawal through Domokos to Thermopylai of the 'Savige' and 'Zarkos' Forces and finally of the 'Lee' Force; the 1^st Armoured Brigade was to cover the withdrawal of the 'Savige' Force to Larissa and thereafter the withdrawal of the Australian 6^th Division, under whose command it would come, and overseeing the withdrawal of 'Allen' Force, which was to move along the same route as the New Zealand 2^nd Division. The British and commonwealth forces remained under attack throughout their withdrawal.

On the morning of 18 April, the Battle of Tempe Gorge, as the the struggle for the Pinios gorge was otherwise known, was over when German armoured infantry crossed the river on floats and men of the 6^th Gebirgsdivision worked their way around the New Zealand battalion, which was then dispersed. On 19 April, the first elements of the XVIII Gebirgskorps entered Larissa and took possession of its airfield, which the British had abandoned without demolishing the supply dump. The German seizure of 10 truckloads of rations and fuel enabled the spearhead units to continue their advance without pause. The port of Volos, where the British had re-embarked many units in the course of the last few days, fell on 21 April to the Germans, who captured large quantities of valuable Diesel fuel and crude oil.

As the German forces pressed deeper into Greece, Antistrátegos Georgios Tsolakoglou’s Epiros Army Section finally received permission to retreat, but it 13 April before the first Greek elements began to withdraw toward the Pindos mountains. The Allied retreat to Thermopylai uncovered a route across the Pindos mountains by which the Germans might flank the Greek army in a rearguard action, and the Infanterieregiment (mot.) 'Leibstandarte SS Adolf Hitler' was assigned the mission of cutting off the Epiros Army Section’s line of retreat from Albania by driving to the west toward the Metsovon pass, and thence to Ioánnina On 14 April, there was heavy fighting in the Kleisoura pass, where the Germans blocked the Greek withdrawal. By now this withdrawal extended across the whole of the Albanian front, with the Italians in only hesitant pursuit.

Papagos rushed Greek units to the Metsovon pass, where he expected the next German attack. On 18 April there began a battle between several Greek units and the Infanterieregiment (mot.) 'Leibstandarte SS Adolf Hitler', which had by then reached Grevena. The Greeks lacked the weapons and other equipment needed to wage an effective battle against a motorised unit, and as a result were soon encircled and overwhelmed. The Germans pressed forward and on 19 April captured Ioánnina, the key point on the line of communications and supply for the Epiros Army Section.

On 20 April, Tsolakoglou accepted that the situation of his Epiros Army Section was hopeless and offered to surrender the 14 divisions of his army, but to the Germans rather than the Italians. Under Hitler’s strict instructions, Dietrich parleyed with the Greeks in total secrecy and accepted the surrender. When he learned of this, an outraged Mussolini ordered attacks on the surrendering Greek forces, which repulsed the Italian efforts. It took a personal representation from Mussolini to persuade Hitler that there should be an Italian involvement in the armistice which was concluded on 23 April. This allowed Greek soldiers to go home after the demobilisation of their units rather than being seized as prisoners of war, and the Greek officers were permitted to retain their side arms.

As early as 16 April, the German command realised that British ships were evacuating troops from the ports of Vólos in Thessaly and Piraeus in Attica, and from this time onward the campaign assumed the character of German pursuit rather than a German invasion. For the Germans, it was now primarily a question of maintaining contact with the retreating British and commonwealth forces and defeating their evacuation plans, and as a result the Germans withdrew their infantry divisions, which lacked the mobility for such an effort. The 2^nd Panzerdivision, 5^th Panzerdivision, 5^th Gebirgsdivision, 6^th Gebirgsdivision and Infanterieregiment (mot.) 'Leibstandarte SS Adolf Hitler' were therefore the formations and units with which the Germans undertook their pursuit of the retreating British and commonwealth forces.

To allow an evacuation of the main body of British forces, Wilson ordered the rearguard to make a last stand at the historic Thermopylai pass, the gateway to Athens. Here Freyberg had been allocated the task of defending the coastal pass with Mackay defending the inland village of Brallos. In the New Zealand sector, the 5^th Brigade was deployed along the coastal road, the foothills to the south of Lamia and on the Spercheios river, the 4^th Brigade on the right where it had established coast-watching patrols, and the 6^th Brigade in reserve. In the Australian sector the 19^th Brigade, comprising the 2/4^th and 2/8^th Battalions, defended Brallos. On 19 April, the 2/1^st and 2/5^th Battalions were placed under the command of Vasey, and that day and during the early hours of the next, the 2/11^th Battalion rejoined the brigade. Freyberg and Mackay had told their subordinates that there would be no more withdrawals as both were unaware of discussions at higher command levels about the evacuation.

When the order to retreat was received on the morning of 23 April, it was decided that each of the two positions would be held by one brigade. These were the Australian 19^th Brigade and New Zealand 6^th Brigade, which were to hold the passes as long as possible, allowing the other units to withdraw. The Germans attacked at 11.30 on 24 April, met fierce resistance, lost 15 tanks and sustained considerable casualties. The Australians and New Zealanders held out the entire day, and with their delaying action accomplished, the two brigades fell back in the direction of the evacuation locations. The Panzer units seeking to press the German pursuit were considerably slowed by their need to navigate the road leading across the pass, which had very steep gradients and difficult hairpin bends.

After abandoning Thermopylai, the British and commonwealth rearguard withdrew to an improvised switch position to the south of Thebes, which was the last obstacle to the north-west of Athens. The motorcycle battalion of the 2^nd Panzerdivision, which had crossed to the island of Euboia to seize the port of Khalkis and had subsequently returned to the mainland, was given the mission of outflanking the British rearguard. The motorcycle troops encountered only slight resistance, and on the morning of 27 April the first German troops entered Athens, followed by armoured cars, tanks and infantry. Here the Germans seized large quantities of petrol, oil and lubricants, several thousand tons of ammunition, 10 trucks loaded with sugar and 10 truckloads of other rations in addition to various other equipment, weapons and medical supplies. The population of Athens had been expecting the Germans for several days and confined themselves to their homes with their windows shut. The Germans drove straight to the Akropolis and raised the Nazi flag.

During the morning of 15 April, Wavell, the British commander-in-chief Middle East Command, sent Wilson a message saying 'We must of course continue to fight in close cooperation with Greeks but from news here it looks as if early further withdrawal necessary.' When he was in Greece between 11 and 13 April, Wavell had warned Wilson that he must expect no reinforcements and authorised Major General F. W. de Guingand, of the Joint Planning Staff of the GHQ Middle East, to discuss evacuation plans with certain responsible officers, which de Guingand had already started on his own initiative. Nevertheless, the British could not at this stage adopt or even mention any such course of action as, for political reasons, the suggestion had to come from the Greek government. On the following day, Papagos suggested to Wilson that 'W' Force be withdrawn. Wilson informed GHQ Middle East of this, and on 17 April Rear Admiral H. T. Baillie-Grohman was sent to Greece to prepare the evacuation, which was planned as 'Demon'. On the same day Wilson travelled to Athens, where he attended a conference with the king, Papagos, d’Albiac and Rear Admiral C. E. Turle, the British naval attaché in Greece. In the evening, after telling the king that he felt he had failed in the task entrusted to him, prime minister Koryzis committed suicide.

On 21 April, the final decision to evacuate the British and commonwealth forces from mainland Greece to Crete and Egypt was taken, and an initial contingent of some 5,200 men, mostly of the New Zealand 5^th Brigade, were evacuated on the night of 24 April from Porto Rafti in eastern Attica, while the New Zealand 4^th Brigade remained to block the narrow road to Athens. On 25 April the few remaining RAF squadrons left Greece, d’Albiac establishing his new headquarters in Heraklion on the island of Crete, and some 10,200 Australian troops were evacuated from Nafplio and Megara in the Peloponnese. Another 2,000 men had to wait until 27 April after Ulster Prince ran aground in shallow waters close to Nafplio. It was only at this stage that the Germans realised that the evacuation was now also taking place from the ports of the eastern Peloponnese.

On 25 April the Germans launched their 'Hannibal' (ii) airborne operation to seize the bridges over the Corinth Canal with the double aim firstly of cutting off the British line of retreat and secondly of securing their own later means of access across the isthmus into the Peloponnese. The attack met with initial success, until a stray British shell destroyed the bridge.

Assembled in Ioánnina, the Infanterieregiment (mot.) 'Leibstandarte SS Adolf Hitler' was now driving along the western foothills of the Pindos Mountains via Arta to Messolongi on the northern side of the western end of the Gulf of Corinth, and crossed to Patrai in the Peloponnese to open the possibility of an advance to the isthmus from the west. Reaching the isthmus at 17.30 on 27 April, the SS force learned that the paratroopers had already been relieved by army units advancing from Athens.

The 11,636-ton Dutch troop ship Slamat was part of a convoy evacuating about 3,000 British, Australian and New Zealand troops from Nafplio in the Peloponnese and, while steaming to the south off the east coast of the Peloponnese, during the morning of 27 April, came under attack by a Staffel of nine Junkers Ju 87 dive-bomber of Major Graf Clemens von Schönborn-Wiesentheid’s Stukageschwader 77. Slamat was damaged and set on fire. The British Diamond rescued about 600 survivors and Wryneck came to her aid, but as the two destroyers made for for Souda Bay in Crete another Ju 87 attack sank them both. The total number of deaths from the three sinkings was almost 1,000. Only 27 men from Wryneck, 20 crew from Diamond, 11 crew and eight evacuated soldiers from Slamat survived.

The completion of a temporary bridge across the Corinth Canal made it possible for elements of the 5^th Panzerdivision to pursue the British and commonwealth forces across the Peloponnese. Driving via Argos to the port of Kalamata, from which the majority of the British and commonwealth units had already started to depart, on 29 April the German army forces reached the south coast of the Peloponnese, where they were joined by SS troops arriving from Pírgos on the west coast of the Peloponnese. In overall terms, the fighting in which the German forces found themselves engaged in the Peloponnese took the form of small-scale engagements with isolated groups of British troops who had been unable to reach the evacuation point. The German attack came days too late to cut off the bulk of the British troops in central Greece, but isolated the Australian 16^th and 17^th Brigades.

By 30 April the evacuation of about 50,000 soldiers had been completed, but 'Demon' was heavily contested by German warships, which sank at least 26 troop-laden ships as well as many warships. The Germans captured around 8,000 British and commonwealth troops, including 2,000 Cypriots and Palestinians, as well as a number of Yugoslav troops in Kalamata before they could be evacuated, and also freed many Italians from prisoner of war camps.

The German casualties in the Greek campaign were 1,685 men killed and 3,750 wounded, compared with British losses of 12,700 men killed and 9,000 taken prisoner, and Greek losses (in a six-month campaign including the war with Italy in Albania) of 15,700 men dead and 218,000 taken prisoner. During their six-month involvement the Italians had lost 13,755 men dead, 50,875 wounded, 25,000 missing and 12,370 suffering from frostbite.

On 13 April, Hitler had issued his Führerweisung Nr 27 about the later stages of the Greek campaign, and this included his preliminary instructions for the occupation policy for Greece, which was finalised in the Führerweisung Nr 31 of 9 June. Greece was divided between Germany, Italy and Bulgaria. Germany controlled the north-eastern corner opposite European Turkey, Macedonia, Athens and the islands of Salamis and Aigina off it, the western three-quarters of Crete after its seizure in 'Merkur', Milos and Amorgos in the Cyclades islands group, and in the Aegean Sea the islands of Patmos, Chios, Lésbos, Agios Eustratios and Lemnos. Bulgaria received Thrace (between the Struma river and a line of demarcation running through Alexandroupoli and Svilengrad to the west of the Evros river, which had been occupied on the day that Tsolakoglou had offered his surrender, and from July 1943 extended westward to a line just short of Thessaloníki) and the islands of Thasos and Samothrace. Italy was given the rest of the country on the mainland and in the islands of the Ionian and Aegean Seas to supplement those they already possessed in the Dodecanese islands group.

Italian troops started to occupy the islands of the Ionian and Aegean Seas on 28 April, on 2 June they occupied the Peloponnese, on 8 June Thessaly, and on 12 June most of Attica.

King Giorgios II and his government departed mainland Greece for Crete on 25 April, but were forced to leave Crete for Egypt on 24 May after the German 'Merkur' invasion of Crete.

The Greek campaign ended with a complete German, and to a lesser extent Italian, victory. The Greeks lacked the modern military strength and industrial infrastructure which might have allowed them to mount a more effective defence, and the UK and its commonwealth lacked the military resources to permit them to carry out simultaneous large-scale operations in North Africa and the Balkans. Moreover, even had they been able to block the Axis advance, the British and commonwealth forces would have been unable to exploit the situation by a counter-thrust across the Balkans. However, the British came very close to holding Crete and perhaps other islands which could have provided air support for naval operations throughout the eastern Mediterranean.

Thus the reasons for the complete Axis victory in the Greek campaign included the German superiority in ground forces and equipment; the commitment of the bulk of the Greek army to fighting the Italians on the Albanian front; German air supremacy combined with the inability of the Greeks to provide the RAF with adequate airfields; the inadequacy of the British and commonwealth expeditionary force; the technically impoverished nature of the Greek forces and their overall shortage of modern equipment; inadequate port, road and railway facilities; the absence of a unified command and the resultant lack of effective co-operation between the British, Greek and Yugoslav forces; Turkey’s strict neutrality; and the early collapse of Yugoslav resistance.

After the Allied defeat in Greece, the decision to send British and commonwealth forces into Greece faced fierce criticism in the UK. Field Marshal Sir Alan Brooke, Chief of the Imperial General Staff during World War II, considered intervention in Greece to be a strategic error as it denied Wavell the necessary reserves to complete the conquest of the Italian 'empire' in North Africa, or to withstand the combined Axis offensive to the east in March 1941 after the 'Sonnenblume' arrival of German forces in Libya. Thus the diversion of British and commonwealth forces to Greece prolonged the North African campaign, which otherwise might have been successfully concluded during 1941.