'Sonnenblume' was the Axis movement of Generalleutnant Erwin Rommel’s Befehlshaber der deutschen Truppen in Libyen and Sperrverband 'Libyen' (the Deutsches Afrikakorps from 21 February) to North Africa (8/11 February 1941).

The North African war had started at a low intensity between the Italians, who were Germany’s allies in the Axis, and the British with their commonwealth allies. In June 1940, the month in which Italy entered World War II, the Italian forces in North Africa comprised some 250,000 men in nine regular divisions, three 'Camicie Nere' (blackshirt) divisions, and two North African divisions under the command of Maresciallo d’Italia Rodolfo Graziani, who controlled Generale di Corpo d’Armata Italo Garibaldi’s 5a Armata in western Libya facing the French in Tunisia and Generale di Corpo d’Armata Mario Berti’s (from 23 December Generale di Corpo d’Armata Giuseppe Tellera’s) 10a Armata in eastern Libya facing the British in Egypt.

The British had 36,000 men in Egypt and 27,000 in Palestine, under the overall command of General Sir Archibald Wavell. The force on the Egyptian border with Italian Libya was Major General R. O’Connor’s Western Desert Force, which comprised Major General M. O’Moore Creagh’s 7^th Armoured Division, Major General N. Beresford-Pierce’s Indian 4^th Division and Major General B. C. Freyberg’s New Zealand Division. Despite its very considerable numerical inferiority, the Western Desert Force responded to the Italian declaration of war with a series of raids, and this persuaded the Italians to reach a gross overestimation of the force facing them. However, at the urging of Benito Mussolini, the Fascist dictator of Italy, Graziani finally started to move his forces with great caution across the border and occupied Sidi Barrani, but instead of pushing their advance farther to the east allowed them to halt and embark on the construction of 10 fortified camps between Maktila on the coast, to the east of Sidi Barrani, and Sofafi to the south-west in the desert.

The British plans for a counter-offensive were aided by the arrival of a major convoy delivering, in addition to other equipment, 50 infantry tanks. Wavell and General Sir Henry Maitland Wilson, who commanded the forces in Egypt, now planned a limited offensive as 'Compass' to recapture Sidi Barrani. If successful, this could be extended to the capture of Tobruk farther to the west, and then to advance deeper into Libya.

The two fronts were separated by some 70 miles (110 km), and the Western Desert Force began its approach on the night of 6/7 December from the area of Abar el Kanaysis mid-way between the Qattara Depression and the cost, laagered in the desert on the following day, and during the afternoon of 8 December reached a point known as 'Piccadilly' on the east/west railway line. This position was to the east of the southern group of four Italian camps, which lay to the south-west of the other six. The 7^th Armoured Division then swung through this gap to cut the coast road at Buq Buq, while the Indian 4^th Division and 7^th Royal Tank Regiment attacked Nibeiwa camp from the rear early on 9 December. The camp fell swiftly and by the evening Tummar West camp had also been taken. Meanwhile an independent column, 'Selby' Force, had advanced along the coast road towards Sidi Barrani, which was attacked and taken on 10 December, yielding 38,000 Italian prisoners.

Wavell now had to withdraw the Indian 4^th Division for service in Sudan, and there was a delay while it was replaced by Major General Iven G. Mackay’s Australian 6^th Division. This formation began the next stage of the advance by capturing Bardia and another 38,000 Italians on 3 January 1941.

The Italians had now lost almost eight divisions and were in full retreat, but the British supply lines were becoming overstretched, and Wavell was warned that he would soon have to withdraw troops to be sent to Greece, which was already at war with Italy and now coming under threat of German attack. However, Tobruk was taken on 22 January, Derna was abandoned by the Italians seven days later and occupied the following day, and by 9 February the British reached El Agheila, where they were halted.

Despite the fact that there was no apparent resistance farther to the west, forces now had to be withdrawn to aid Greece, which had been invaded by the Italians, and only a thin covering force could be left to guard the new territories.

Adolf Hitler, the German leader, decided unwillingly on 11 January 1942 that he had little option but to aid his Italian ally in North Africa in defensive rather than offensive operations. This decision was formalised in Hitler’s Führerweisung Nr 22 of the same day, and the first elements of what would soon become the Deutsches Afrikakorps were therefore moved to Italy and transported by German and Italian ships to North Africa in 'Sonnenblume' on 8/12 February 1942 with the strength (including armoured units) to serve as the Sperrverband 'Libyen' (Libyan blocking group) for the defence of Tripolitania, the western half of Italy’s Libyan colony whose Cyrenaica eastern portion had been taken by the British. Thus Generalmajor Johannes Streich’s 5^th leichte Division and Generalmajor Heinrich von Prittwitz und Gaffron’s 15^th Panzerdivision were to become the primary constituents of Rommel’s new Deutsches Afrikakorps.

After a protracted night bombing of Malta by aircraft of General Hans Geisler’s X Fliegerkorps on 7/8 February, with the object of keeping the British air and sea offensive forces off balance, the first German troops and matériel departed Naples for Tripoli on 8 February in the 4,768-ton Ankara, 2,596-ton Arcturus and 2,140-ton Alicante. These transports were escorted by the Italian destroyer Turbine and the torpedo boats Orsa, Cantore and Missori as well as aircraft of the X Fliegerkorps. From later in the same day to a time on 10 February, the convoy sheltered at Palermo after a report that the British warships of Vice Admiral Sir James Somerville’s Gibraltar-based Force 'H' had been sighted, but on 11 February the convoy resumed its passage, reaching Tripoli on the following day.

Already in North Africa were the first elements of the X Fliegerkorps detached from Sicily under the command of Generalmajor Stefan Fröhlich, the Fliegerführer 'Afrika'. The second convoy carrying the Deutsches Afrikakorps followed in the form of the 4,205-ton Adana, 2,447-ton Aegina, 7,764-ton Kybfels and 5,954-ton Ruhr, which left Naples on 12 February and reached Tripoli two days later under escort of the Italian destroyer Camicia Nera and torpedo boat Procione.

Additional equipment and supplies for the Deutsches Afrikakorps followed on 1/3 March when a convoy of four transports, escorted by the Italian torpedo boats Clio, Orione and Pegaso, reached Tripoli from Naples.

At the insistence of Hitler, whose allocation of the 15^th Panzerdivision was dependent on their compliance, the Italians had agreed to pull back no farther than Sirte in the Gulf of Sirte, so maintaining at least a vestigial presence in Cyrenaica, where a new commander, Generale di Corpo d’Armata Italo Gariboldi, was trying to restore the cohesion and morale of the Italian 10a Armata. Reaching Tripoli on 12 February to take up his new command, Rommel appears to have been little concerned with the letter of his orders and started to send patrols away to the east. By the end of February these patrols were clashing with the British near Sirte, and by the middle of March Rommel had realised that the British not only intended to remain on the defensive but were in fact reducing their strength.

By 1 March Rommel had come to the conclusion that the best way to defend Tripolitania was by the launch of an offensive from Sirte to take the marshy region 20 miles (32 km) to the west of El Agheila, which could be held by small armoured forces behind mine and wire defences. By 13 March units of the 5^th leichte Division had moved up to this point, found no British opposition and, with Generale di Brigata Francesco Antonio Arena’s 132a Divisione corazzata 'Ariete', set about improvising defences. With Tripolitania thus secure, Rommel’s fertile mind began to envisage greater things when Axis intelligence confirmed that most of the Western Desert Force had been pulled back to Egypt, leaving the defence of Cyrenaica to the precarious corps command of Lieutenant General P. Neame’s Cyrenaica Command with Major General M. D. Gambier-Perry’s 2^nd Armoured Division (two understrength brigades in the region of Mersa Brega north-east of El Agheila), Major General Leslie J. Morshead’s Australian 9^th Division (one full-strength and two understrength brigades in the region of the Jebel Akhdar between Benghazi and Derna) and Brigadier E. W. D. Vaughan’s Indian 3^rd Motorised Brigade (in El Adem just to the south of Tobruk).

The British believed that there would be no Axis offensive, and Neame was ordered to maintain a static defence, though in the event of an Axis drive he was given authority to fall back, as slowly as possible, with the object of buying time for reinforcements to arrive after a period of some two months.

Rommel now suggested to Gariboldi, his immediate superior, that their combined forces should launch a surprise attack before the onset of summer weather in May. Gariboldi agreed, and the two commanders secured permission for an offensive to retake Cyrenaica and then (with enormous optimism given the state of Axis reserves and lines of communication) advance into Egypt with the longer-term possibility of an offensive to the Suez Canal. The attack started on 24 March, when the Germans seized El Agheila as a prelude to an advance by the 5^th leichte Division, Generale di Divisione Brunetto Brunetti’s 27a Divisione autotrasportabile 'Brescia' and Arena’s 132a Divisione corazzata, later supplemented by parts of the 15^th Panzerdivision and Generale di Brigata Giorgio Masina’s 102a Divisione motorizzata 'Trento'. Pushing forward from El Agheila, the 5^th leichte Division attacked the 2^nd Armoured Division at Mersa Brega, and after fierce fighting was halted. The British did not counterattack, however, and were then forced to pull back. By 2 April the Germans were at Agedabia on the south-eastern corner of the Gulf of Sirte with the options of advancing to the north in the direction of Benghazi, to the north-east in the direction of Msus and Mechili, and to the east in the direction of Tengeder in order to threaten the British lines of communication.

In response to the growing Axis threat, Wavell had first taken over direct command, and then brought in O’Connor to act as Neame’s adviser.

On 4 April Rommel attacked in all three directions, and his forces met little resistance as the 2^nd Armoured Division had fallen back. The fastest-moving Axis formation was that in the south, which reached Tengeder on 5 April and Mechili, on the southern edge of the Jebel Akhdar, during the following day. However, it was too weak to attack Brigadier G. A. Quale’s Indian 3^rd Brigade, which had moved forward to occupy the place. The appearance of this German force threatened to cut the British lines of communication, and the Australian 9^th Division began to withdraw from the coastal town of Derna to which it had already retreated from Benghazi. On 8 April the remnant of the 2^nd Armoured Division, which had lost most of its tanks through mechanical failure, and the Indian 3^rd Brigade were overwhelmed at Mechili. Meanwhile the British were reinforcing the vital port town of Tobruk with elements of Major General John D. Laverack’s Australian 7^th Division.

The first German units arrived piecemeal on 10/11 April and an improvised attack on 11 April failed. It was not until 14 April that the 5^th leichte Division made a major assault from the south, but its initial penetration ran into heavy artillery fire and counterattacks, and by the afternoon the Germans had been forced to retreat. The situation now stabilised, with Italian units replacing the German units which were preparing to cross the Egyptian frontier. On 25 April the Germans struck at Halfaya Pass and by the following day had pushed the British back to the line linking Buq Buq and Sofafi. On 30 April Rommel made a full-scale attempt to capture Tobruk, but though a salient was pushed into the western sector, after four days fighting it was contained.

Thus by 25 April the exhausted Axis forces had pushed through the Halfaya Pass on Egypt’s western frontier before finally coming to a halt after a devastating campaign which had returned Cyrenaica to Axis control, and on 11 April had cut off within Tobruk the Australian 9^th Division reinforced by one brigade of the Australian 7^th Division. The defensive nature of 'Sonnenblume' had been completely forgotten, and the emergence of a new pattern of warfare in the Western Desert had been signalled.