Operation Battle of Monte Cassino

The 'Battle of Monte Cassino' was fought between Allied and German forces for the abbey-topped mountain above the town of Cassino (17 January/18 May 1944).

Te battle took the form of a series of four Allied assaults as part of the Allied objective of breaking through the 'Gustav-Linie' and advancing toward Rome.

At the beginning of 1944, the western half of the German defences of the 'Gustav-Linie' was anchored by the forces holding the Rapido/Gari, Liri and Garigliano river valleys and several of the surrounding peaks and ridges. At Monte Cassino, a historic hilltop abbey founded in 529 by St Benedict of Nursia dominated the nearby town of Cassino and the entrances to the Liri and Rapido river valleys. Lying in a protected historic zone, the abbey had been left unoccupied by the Germans, although they did man some positions set into the slopes below the abbey’s walls.

Repeated German artillery attacks on Allied attacking troops caused the latter’s leaders to conclude, wholly incorrectly, that the German were using the abbey as an observation post if not an actual element of the 'Gustav-Linie' defences. These Allied suspicions escalated along with the casualty list and, in spite of evidence to the contrary, the abbey was marked for destruction. On 15 February 1944, US bombers dropped 1,400 tons of high explosive bombs, causing extensive damage, and German Fallschirmjäger paratroopers then occupied the area and established defensive positions amid the ruins, which constituted excellent defensive positions.

Between 17 January and 18 May, Monte Cassino and the 'Gustav-Linie' defences were attacked on four separate occasions by Allied troops. On 16 May, men of Generał dywizji Władysław Anders’s Polish II Corps launched one of the final assaults on the German defensive position as part of a 20-division assault along a 20-mile (32-km) front. On 18 May, a Polish flag followed by the British flag was raised over the ruins. Following this Allied victory, the German 'Senger-Linie' collapsed on 25 May, and the German defenders were driven from their positions. The capture of Monte Cassino cost the Allied nations some 55,000 casualties, with German losses estimated at around 20,000 killed and wounded.

The 'Avalanche' landings on Italy’s western coast in September 1943 by two Allied armies, following two months after the Allied 'Husky' (i) landings in Sicily during July, commanded by General the Hon. Sir Harold Alexander, commanding the Allied 15th Army Group (later retitled the Allied Armies in Italy), were followed by an advance to the north on two fronts, one on each side of the Apennine central mountain range forming the spine of Italy. On the western front, the US 5th Army, commanded by Lieutenant General Mark W. Clark, which had suffered heavy casualties during the 'Avalanche' main landing at Salerno in September, moved from the main base of Naples up the Italian 'leg', and on the eastern front the British 8th Army, commanded by General Sir Bernard Montgomery, advanced up the coast of the Adriatic sea.

Clark’s 5th Army made slow progress in the face of difficult terrain, adverse weather and skilful German defence. The Germans were fighting from a series of prepared positions in a manner designed to inflict maximum damage, then pulling back after buying the time needed for the construction of the 'Gustav-Linie' defensive positions to the south of Rome, the capital of Italy. The original estimates that Rome would fall by October 1943 therefore proved to be far too optimistic.

Although in the east the German defensive line had been breached on the Adriatic Sea front and Ortona had been captured by the Canadian 1st Division, the advance had come to a halt with the onset of winter blizzards at the end of December, making close air support and movement in the jagged terrain impossible. The route to Rome from the east using Highway 5 to drive westward across Italy thus ceased to be a viable option, leaving the routes from Naples to Rome, Highways 6 and 7, as the only possibilities. Highway 7 also followed the west coast, but in the area to the south of Rome ran into the Pontine Marshes, which the Germans had flooded.

Highway 6 ran through the Liri river valley, dominated at its southern entrance by the rugged mass of Monte Cassino above the town of Cassino. Excellent observation from the peaks of several hills allowed the German defenders to detect Allied movement and drop highly accurate artillery fire, so preventing any northward advance. Running across the Allied line was the fast-flowing Rapido river, which rose in the central part of the Apennine mountains, flowed through Cassino, where it joined the Gari river, which was erroneously identified as the Rapido river, and across the entrance to the Liri river valley. There the Liri river joined the Gari river to form the Garigliano river, which continued on to the Tyrrhenian sea.

With its heavily fortified mountain defences, difficult river crossings and valley head flooded by the Germans, Cassino was the linchpin of the 'Gustav-Linie', the most formidable line of the defensive positions constituting the 'Winter Line', a series of three lines designed to defend the western section of Italy, focused around the town of Monte Cassino, through which ran the important Highway 6 which led uninterrupted to Rome. Despite its potential excellence as an observation post, because of the 14th century Benedictine abbey’s historical significance, the German commander in Italy, Generalfeldmarschall Albert Kesselring, ordered German forces not to include it in their defensive positions and informed the Vatican and the Allies accordingly in December 1943. Nevertheless, some Allied reconnaissance aircraft maintained they had observed German troops inside the monastery. While this remains unconfirmed, it is clear that once the monastery had been destroyed its ruins were occupied by the Germans and proved better cover for their emplacements and troops than any intact structure could have offered.

The plan developed by Clark, commander of the US 5th Army, was for the British X Corps, under the command of Lieutenant General Sir Richard McCreery, on the left of a 20-mile (32-km) front, to attack on 17 January 1944 across the Garigliano river near the coast using Major General G. C. Bucknall’s (from 22 January Major General P. G. S. Gregson-Ellis’s) 5th Division and Major General G. W. R. Templer’s 56th Divisions. Major General J. L. I Hawkesworth’s British 46th Division was to attack on the night of 19 January across the Garigliano river below its junction with the Liri river in support of the main attack by Major General Geoffrey Keyes’s US II Corps on its right. The main central thrust by the US II Corps was to begin on 20 January with Major General Fred L. Walker’s US 36th Division making an assault across the swollen Gari river 5 miles (8 km) downstream of Cassino. Simultaneously, Général Alphonse Juin’s Corps Expéditionnaire Français would continue its right-hook move toward Monte Cairo, the hinge to the 'Gustav-Linie' and 'Hitler-Linie' defensive lines. Clark did not believe there was much chance of an early breakthrough, but felt that the attacks would draw German reserves away from the Rome area in time for the 'Shingle' assault at Anzio, just to the south of the Italian capital, where Major General John P. Lucas’s US VI Corps (British 1st Division, US 3rd Divisions, US 504th Parachute Regimental Combat Team, US Army Rangers, British commandos, Combat Command B of the US 1st Armored Division, and supporting units) was due to make an amphibious landing on 22 January. It was hoped that the Anzio landing, with the benefit of surprise and a rapid move inland to the Alban Hills, which command both Highways 6 and 7, would so threaten the rear of the defenders of the 'Gustav-Linie' and supply lines that it might just unsettle the German commanders and cause them to withdraw from the 'Gustav-Linie' to positions north of Rome. While this would have been consistent with the German tactics of the previous three months, Allied intelligence had not understood that the German strategy of fighting retreat had been developed and implemented for the sole and specific purpose of providing time to prepare the 'Gustav-Linie', on which the Germans intended to make their stand. The intelligence assessment of Allied prospects was therefore over-optimistic.

The US 5th Army had reached the 'Gustav-Line' only on 15 January after six weeks of heavy fighting to advance the last 7 miles (11.25 km) through the 'Bernhardt-Linie' positions and in the process sustained 16,000 casualties. The 5th Army hardly had time to prepare the new assault, let alone take the rest and reorganisation it needed after three months of attritional fighting to thc north from Naples. However, because the Allies' Combined Chiefs-of-Staff had decided to make landing craft available only until early February, as these were required for the 'Neptune' (iii) amphibious first stage of 'Overlord' in Normandy, 'Shingle' had to take place late in January with the co-ordinated attack on the 'Gustav-Linie' some three days earlier.

The first Allied assault was made on 17 January. Near the coast, the British 56th and 5th Divisions forced a crossing of the Garigliano river, followed some two days later by the British 46th Division on their right, causing General Fridolin von Senger und Etterlin, commander of the XIV Panzerkorps and responsible for the 'Gustav-Linie' defences on the south-western half of the line, some serious concern about ability of Generalleutnant Bernhard Steinmetz’s 94th Division to hold the line. Responding to von Senger und Etterlin’s concerns, Kesselring ordered Generalleutnant Walter Fries’s 29th Panzergrenadierdivision and Generalleutnant Ernst-Günther Baade’s 90th Panzergrenadierdivision from the Rome area to provide reinforcement. There has been speculation as to what might have been if the X Corps had possessed the reserves to exploit its success and make a decisive breakthrough. The corps did not have the extra men, however, but there would certainly have been time to alter the overall battle plan and cancel or modify the central attack by the US II Corps to make men available to force the issue in the south before the German reinforcements could get into position. As it happened, the headquarters of the 5th Army failed to appreciate the fragility of the German position and the plan remained unchanged. The two divisions from Rome had arrived by 21 January and stabilised the German position in the south. In one respect, however, the plan was working inasmuch as Kesselring’s reserves had been drawn to the south. The X Corps' three divisions suffered some 4,000 casualties during the period of this first battle.

The central thrust by Walker’s US 36th Division got under way three hours after sunset on 20 January. The lack of time to prepare meant that the approach to the river was still hazardous, as a result of the area’s uncleared mines and booby traps, and the task of an opposed river crossing lacked the necessary planning and rehearsal. Although one battalion of the 143rd Infantry was able to get across the Gari river on the southern side of San Angelo and two companies of the 141st Infantry on the northern side, they were isolated for most of the time and Allied armour was unable to get across the river, leaving the infantrymen highly vulnerable to counterattack by the tanks and assault guns of Generalleutnant Eberhard Rodt’s 15th Panzergrenadierdivision. The southern group was forced back across the river by the middle of the morning on 21 January. Keyes pressed Walker to renew the attack immediately and, once more, the two regiments attacked but with no more success against the well dug-in 15th Panzergrenadierdivision: the 143rd Infantry got the equivalent of two battalions across river, but, once again, there was no armoured support, and the infantrymen were devastated after the arrival of daylight on the following day. The 141st Infantry also crossed in two-battalion strength and, despite the lack of armoured support, managed to advance 0.6 mile (1 km). However, with the coming of daylight, the 141st Infantry was also cut down and by the evening of 22 January, had virtually ceased to exist: only 40 men made it back to the Allied lines.

The assault had been a costly failure, the 36th Division losing 2,100 men killed, wounded or missing in 48 hours.

The next attack was launched on 24 January. The US II Corps, with Major General Charles W. Ryder’s 34th Division spearheading the attack and French colonial troops on its right flank, launched an assault across the flooded Rapido river valley to the north of Cassino and into the mountains behind with the intention of then wheeling to the left and attacking Monte Cassino from high ground. Whilst the task of crossing the river would be easier inasmuch as the Rapido river upstream of Cassino was fordable, the flooding made movement on the approaches on each side very difficult. In particular, armour could move only on paths laid with steel matting, and it took eight days of bloody fighting across the waterlogged ground for 34th Division to push back Generalleutnant Friedrich Franek’s 44th Reichsgrenadierdivision 'Hoch- und Deutschmeister' and establish a foothold in the mountains.

On the right, Général de Brigade André M. Dody’s 2ème Division d’Infanterie Marocaine made good initial progress against Generalleutnant Dr Julius Ringel’s 5th Gebirgsdivision, gaining positions on the slopes of its key objective, Monte Cifalco. Forward units of Général de Division Joseph de Goislard de Monsabert’s 3ème Division d’Infanterie Algérienne had also bypassed Monte Cifalco to capture Monte Belvedere and Colle Abate. Juin was convinced that Cassino could be bypassed and the German defences unhinged by this northerly route, but his request for reserves with which to maintain his advance’s momentum was refused and the one available reserve regiment (of the 36th Division) was sent to reinforce the 34th Division. By 31 January the French had been ground to a halt with Monte Cifalco, which had a clear view of the French and US flanks and supply lines, still in German hands. The two French North African divisions sustained 2,500 casualties in their struggles around Colle Belvedere.

It became the task of the US 34th Division, reinforced temporarily by the 142nd Infantry of the US 36th Division that had been held in reserve and not used during the Rapido river crossing, to fight it way to the south along the linked hilltops towards the intersecting ridge on whose southern end lay Monastery Hill. The division could then break through down into the Liri river valley behind the 'Gustav-Linie' defences. It was very difficult going: the mountains were rocky, strewn with boulders and riven by ravines and gullies. The digging of foxholes in the rocky ground was out of the question, and each feature was exposed to fire from surrounding high points. The ravines were no better since the gorse growing there, far from giving cover, had been sown with mines, booby-traps and concealed barbed wire by the Germans, who had had three months to prepare their defensive positions using dynamite, and to stockpile ammunition and stores. There was no natural shelter, and the weather was wet and freezing cold.

By a time early in February, US infantry had captured a strategic point near the hamlet of San Onofrio, less than 1 mile (1.6 km) from the abbey, and by 7 February one battalion had reached Point 445, a round-topped hill immediately below the abbey and no more than 400 yards (365 m) away. One US squad managed a reconnaissance right up against the cliff-like abbey walls, from which the monks could observe German and US patrols exchanging fire. However, attempts to take Monte Cassino were broken by overwhelming machine gun fire from the slopes below the monastery. Despite its fierce fighting, the 34th Division never managed to take the final redoubts on Hill 593, which was known to the Germans as Calvary Mount, held by the 3/2nd Fallschirmjägerregiment, part of Generalleutnant Richard Heidrich’s 1st Fallschirmjägerdivision, and the dominating point of the ridge to the monastery.

On 11 February, after a final unsuccessful three-day assault on Monastery Hill and Cassino town, the Americans were withdrawn. After two and a half weeks of battle, the US II Corps was worn out. The performance of the 34th Division in the mountains is considered to rank as one of the finest feats of arms carried out by any soldiers during the war, but the division suffered losses of about four out of every five infantrymen, some 2,200 casualties.

At the height of the battle in the first days of February, von Senger und Etterlin had moved the 90th Panzergrenadierdivision from the Garigliano river front to the north of Cassino and had been so alarmed at the rate of his formation’s attrition that he had 'mustered all the weight of my authority to request that the Battle of Cassino should be broken off and that we should occupy a quite new line…a position, in fact, north of the Anzio bridgehead.' Kesselring refused the request. At the crucial moment von Senger und Etterlin was able to commit Generalleutnant Wilhelm Raapke’s 71st Division while leaving the 15th Panzergrenadierdivision, which the 17th Division was to have relieved.

During the battle there had been occasions when the more astute use of reserves might have created situations in which possible success could have been turned into decisive moves. It has been suggested that this failure to capitalise on initial success can be attributed to Clark’s lack of experience, but it is more likely that he merely had too much to do inasmuch as he was responsible for both the Cassino and Anzio offensives. This view is supported by the inability of Major General Lucian K. Truscott, commanding the US 3rd Division to speak to him at a vital juncture of the Anzio break-out at the time of the fourth Cassino battle. Whilst Alexander chose, for perfectly logical co-ordination arguments, to have Cassino and Anzio under a single army commander and to divide the 'Gustav-Linie' front between the US 5th Army and the British 8th Army, now commanded by Lieutenant General Sir Oliver Leese, Kesselring chose to create a separate 14th Army under General Eberhard von Mackensen to fight at Anzio while leaving the 'Gustav-Linie' in the sole hands of General Heinrich von Vietinghoff-Scheel’s 10th Army.

The withdrawn US units were replaced by Lieutenant General Sir Bernard Freyberg’s New Zealand Corps (New Zealand 2nd Division and Indian 4th Division) from the 8th Army on the Adriatic Sea front.

With the US VI Corps under heavy threat at Anzio, Freyberg was under equal pressure to launch a relieving action at Cassino. Once again, therefore, this 'Avenger' (i) battle started before the attackers were fully prepared. Moreover, the corps headquarters did not fully appreciate the difficulty in getting the Indian 4th Division, under the command of Brigadier H. K. Dimoline as Major General F. I. S. Tuker was ill, into place in the mountains and supplying them on the ridges and valleys to the north of Cassino. Freyberg’s plan was a continuation of the first battle, namely an attack from the north along the mountain ridges and an attack from the south-east along the railway line to capture the railway station across the Rapido river less than 1 mile (1.6 km) to the south of the town of Cassino. Success would pinch out the town of Cassino and open the Liri river valley. Freyberg had informed his superiors that he believed, given the circumstances, there was no better than a 50% chance of success.

Increasingly, the opinions of certain Allied officers were fixed on the great abbey of Monte Cassino: in their view it was the abbey, and its presumed use by the Germans as an artillery observation point, that prevented the breach of the 'Gustav-Linie'. The British press and C. L. Sulzberger of The New York Times frequently, convincingly and in often-manufactured detail wrote of German observation posts and artillery positions inside the abbey. The commander-in-chief of the Mediterranean Allied Air Forces, Lieutenant General Ira C. Eaker, accompanied by Lieutenant General Jacob L. Devers, the deputy of General Sir Henry Maitland Wilson, the Supreme Allied Commander of the Mediterranean Theatre, made a personal observation and saw 'a radio mast…German uniforms hanging on a clothesline in the abbey courtyard; [and] machine gun emplacements 50 yards [46 m] from the abbey walls.' Countering this, Keyes, commander of the US II Corps, also flew over the monastery several times, reporting to the headquarters of the 5th Army that he had seen no evidence that the Germans were in the abbey. When informed of the claims of others to have seen seen German troops there, he stated 'They’ve been looking so long they’re seeing things.'

Major General H. K. Kippenberger of the New Zealand Corps headquarters held it was the consensus that the monastery was probably being used as the Germans' main vantage point for artillery spotting since it was so perfectly situated to the role that no army could refrain. There is no clear evidence that the abbey was being so used, but he went on to write that from a military point of view it was immaterial: 'If not occupied today, it might be tomorrow and it did not appear it would be difficult for the enemy to bring reserves into it during an attack or for troops to take shelter there if driven from positions outside. It was impossible to ask troops to storm a hill surmounted by an intact building such as this, capable of sheltering several hundred infantry in perfect security from shellfire and ready at the critical moment to emerge and counter-attack…Undamaged it was a perfect shelter but with its narrow windows and level profiles an unsatisfactory fighting position. Smashed by bombing it was a jagged heap of broken masonry and debris open to effective fire from guns, mortars and strafing planes as well as being a death trap if bombed again. On the whole I thought it would be more useful to the Germans if we left it unbombed.'

Tuker, whose Indian 4th Division would have the task of attacking Monastery Hill, had made his own appraisal of the situation. In the absence of detailed intelligence at 5th Army headquarters, he had found a book of 1879 in a Naples bookshop giving details of the construction of the abbey. In his memorandum to Freyberg, he concluded that regardless of whether the monastery was currently occupied by the Germans, it should be demolished to prevent its effective occupation. He also pointed out that with 150-ft (46-m) high walls made of masonry at least 10 ft (3 m) thick, there were no practical means for field engineers to deal with the place and that bombing with 'blockbuster' bombs would be the only solution since 1,000-lb (454-kg) bombs would be 'next to useless'. Tuker said he could not be induced to attack unless 'the garrison was reduced to helpless lunacy by sheer unending pounding for days and nights by air and artillery'.

On 11 February 1944, Dimoline, the acting commander of the Indian 4th Division, requested a bombing raid. Tuker reiterated his case from a hospital bed in Caserta, where he was suffering a severe attack of a recurrent tropical fever. Freyberg forwarded his request on 12 February. The request was greatly expanded by air force planners, however, and was probably supported by Eaker and Devers, who sought to use the opportunity to showcase the capacity of US air power to support ground operations. Clark and his chief-of-staff, Major General Alfred M. Gruenther, remained unconvinced of the 'military necessity'. When handing over the US II Corps' position to the New Zealand Corps, Brigadier General J. A. Butler, deputy commander of US 34th Division, had said 'I don’t know, but I don’t believe the enemy is in the convent. All the fire has been from the slopes of the hill below the wall.' Finally Clark, 'who did not want the monastery bombed', pinned down Alexander to take the responsibility: 'I said, ''You give me a direct order and we’ll do it,'' and he did.'

The 'Bradman' bombing mission on the morning of 15 February involved 142 Boeing B-17 Flying Fortress four-engined heavy bombers followed by 47 North American B-25 Mitchell and 40 Martin B-26 Marauder twin-engined medium bombers. These aircraft dropped 1,150 tons of high explosives and incendiary bombs on the abbey, reducing the entire top of Monte Cassino to a smoking mass of rubble. Between bomb runs, the II Corps artillery pounded the mountain. Many Allied soldiers and war correspondents cheered as they observed the spectacle. Eaker and Devers watched, and Juin was heard to remark 'no, they’ll never get anywhere this way.' Clark and Gruenther refused to be on the scene and remained at their headquarters. That same afternoon and during the next day an aggressive follow-up of artillery and a raid by 59 fighter-bombers wrought further destruction. The German positions on Point 593 above and behind the monastery were untouched.

Damningly, the air raid had not been co-ordinated with ground commands and thus there was no immediate infantry attack. The timing of the bombing had been driven by the USAAF’s decision to regard it as a separate operation, considering the weather and requirements on other fronts and theatres without reference to local ground forces. Many of the troops had taken over their positions from II Corps only two days earlier, and besides the difficulties in the mountains, preparations in the valley had also been delayed by difficulties in supplying the newly arrived troops with sufficient material for a full-scale assault because of incessantly foul weather, flooding and waterlogged ground. As a result, Indian troops on the Snake’s Head were taken by surprise, while the New Zealand Corps was two days away from being ready to launch its main assault.

Pope Pius XII remained silent after the bombing, but the Vatican’s secretary of state, Cardinal Luigi Maglione, bluntly stated to the senior US diplomat to the Vatican, Harold Tittmann, that the bombing was 'a colossal blunder – a piece of a gross stupidity'.

It is certain from every investigation that followed the event that the only people in the abbey killed by the bombing were 230 Italian civilians seeking refuge. There is no evidence that the bombs dropped on the abbey on that day killed any German troops. However, given the current imprecision of bombing (it was estimated that only 10% of the bombs delivered by the heavy bombers, attacking from high altitude, hit the monastery) bombs did fall elsewhere and killed German and Allied troops alike, although that was unintended. Indeed, 16 bombs hit the 5th Army compound at Presenzano 17 miles (27 km) from Monte Cassino and exploded only yards away from the trailer where Clark was working at his desk.

At first light on the day after the bombing, most of the civilians still alive fled the ruins. Only about 40 people remained: the six monks who survived in the deep vaults of the abbey, their 79-year-old abbot, Gregorio Diamare, three tenant farmer families, orphaned or abandoned children, the badly wounded and the dying. After artillery barrages, renewed bombing and attacks on the ridge by the Indian 4th Division, the monks decided to leave their ruined home with the others who could move at 07.30 on 17 February. The old abbot was leading the group down the mule path toward the Liri river valley, telling his rosary. After they arrived at a German first-aid station, some of the badly wounded who had been carried by the monks were taken away in a military ambulance. After meeting with a German officer, the monks were driven to the monastery of Sant’Anselmo all’Aventino. On 18 February, the abbot met the commander of the XIV Panzerkorps, von Senger und Etterlin. One monk, Carlomanno Pellagalli, returned to the abbey, where he was later seen wandering the ruins. The German paratroopers now in occupation thought he was a ghost, and after 3 April he was not seen again.

It is now known that the Germans had reached an agreement with the Vatican in December 1943 not to use the abbey for military purposes. Following its destruction, men of the 1st Fallschirmdivision when occupied the abbey’s ruins and turned it into a fortress and observation post, which became a serious problem for the attacking Allied forces.

On the night following the bombing, a company of the 1/Royal Sussex Regiment, the British battalion of Brigadier O. de T. Lovett’s Indian 7th Brigade of the the Indian 4th Division, attacked the key Point 593 from its position 70 yards (64 m) away on Snakeshead Ridge. The assault failed, with the company sustaining 50% casualties.

The following night the 1/Royal Sussex Regiment was ordered to attack in full battalion strength. There was a calamitous start. Artillery could not be used in direct support targeting Point 593 because of the proximity and risk of hitting friendly troops. It was planned therefore to shell Point 575, which had been providing supporting fire to the defenders of Point 593. The topography of the land meant that shells fired at Point 575 had to pass very low over Snakeshead Ridge, and in the event some of the shells fell among the gathering assault companies. After reorganising, the attack went in at 00.00. The fighting was brutal and often hand-to-hand, but the determined defence held and the 1/Royal Sussex was beaten back, once again sustaining more than 50% casualties. Over the two nights, the Royal Sussex Regiment lost 12 out of 15 officers and 162 out of 313 men committed to the attack.

It was on the night of 17 February, the main 'Avenger' (i) assault took place. The 4/6th Rajputana Rifles would take on the assault on Point 593 along Snakeshead Ridge with the depleted 1/Royal Sussex Regiment held in reserve. The 1/9th Gurkha Rifles was to attack Point 444. In the meantime, the 1/2nd Gurkha Rifles were to sweep across the slopes and ravines in a direct assault on the monastery. This last was across appallingly difficult terrain, but it was hoped that the Gurkhas, expert in mountain terrain, would succeed. This proved a faint hope. Once again, the fighting was brutal, but no progress was made and casualties were heavy. The Rajputs lost 196 officers and men, the 1/9th Gurkhas 149 and the 1/2nd Gurkhas 96. It became clear that the attack had failed and on 18 February Dimoline and Freyberg called off the attacks on Monastery Hill.

In the other half of the main assault, two companies of the 28th (Moori) Battalion of the New Zealand 2nd Division forced a crossing of the Rapido river and attempted to gain the railway station in Cassino town. The intention was to take a perimeter that would allow engineers to build a causeway for armoured support. With the aid of an almost constant smoke screen laid down by Allied artillery, and which hid the New Zealanders' location from the German batteries on Monastery Hill, the Maoris were able to hold their positions for much of the day. Their isolation and lack of both armoured support and anti-tank guns made for a hopeless situation, however, when an armoured counterattack by two tanks fell on them during the afternoon of 18 February. The Maoris were ordered to pull back to the river when it became clear to headquarters that both the attempts to break through (in the mountains and along the causeway) would not succeed. It had been very close. The Germans had been very alarmed by the capture of the station, and a conversation on record between Kesselring and von Vietinghoff-Scheel, indicates that they had not expected their counterattack to succeed.

For the 'Dickens' third battle, it was decided that while the winter weather persisted, fording the Garigliano river downstream of Cassino town was an unattractive option, as suggested by the first two battles. The 'right hook' in the mountains had also been a costly failure and it was decided to launch twin attacks from the north along the Rapido river valley: one toward the fortified Cassino town and the other toward Monastery Hill. The idea was to clear the path through the bottleneck between these two features to allow access toward the station in the south and so to the Liri river valley. Major General C. F. Keightley’s British 78th Division, which had arrived late in February and was placed under the command of the New Zealand Corps, would then cross the Rapido river downstream of Cassino and start the push to Rome.

None of the Allied commanders was happy with the plan, but it was hoped that an unprecedented preliminary bombing by heavy bombers would prove to be the trump card. Three clear days of good weather were required and for 21 successive days the assault was postponed as the troops waited in the freezing wet positions for a favourable weather forecast. Matters were not helped by the loss of Kippenberger, who was wounded by an anti-personnel mine and lost both his feet. He was replaced by Brigadier G. B. Parkinson. The German 'Sonnenaufgang' counterattack at Anzio had failed and been terminated.

The third battle began 15 March. After the dropping of 750 tons of 1,000-lb (343-kg) bombs fitted with delayed-action fuses, starting at 08:30 and lasting 3.5 hours, the New Zealanders advanced behind a creeping artillery barrage from 746 pieces of artillery. Success depended on taking advantage of the supposed paralysing effect of the bombing, but this was not concentrated: only 50% of the bombs landed 1 mile (1.6 km) or less from the target point and a mere 8% within 1,000 yards (915 m), but the bombing and the shelling had killed about half of the 300 paratroopers in the town. The defences rallied more quickly than expected, however, and the Allied armour was delayed by bomb craters. Nevertheless, success was there for the New Zealanders' taking, but by the time a follow-up assault on the left had been ordered that evening it was too late: the German defences had been reorganised and, more critically and contrary to the forecast, the rain had restarted. Torrents of water flooded bomb craters, turned rubble into a morass and ruined communications, the radio sets being incapable of surviving the constant immersion. The dark rain clouds also blotted out the moonlight, hindering the task of clearing routes through the ruins. On the right, the New Zealanders had captured Castle Hill and Point 165 and, as planned, elements of the Indian 4th Division, now commanded by Major General A. Galloway, had passed through to attack Point 236 and thence Point 435, Hangman’s Hill. In the confusion of the fight, a company of the 1/9th Gurkha Rifles had taken a track avoiding Point 236 and captured Point 435, while the assault on Point 236 by the 1/6th Rajputana Rifles had been repelled.

By the end of 17 March, the Gurkhas held Hangman’s Hill (Point 435), 250 yards (230 m) from the monastery, in battalion strength despite the fact that their line of supply was compromised by the German positions at Point 236 and in the northern part of the town, and while the town was still fiercely defended, New Zealand units and armour had got through the bottleneck and captured the station. However, the Germans were still able to reinforce their troops in the town and were proving adept at slipping snipers back into parts of the town that had supposedly been cleared.

The day of 19 March was planned for the decisive blow in the town and on the monastery, including a surprise attack by tanks of 20th Armoured Regiment working their way along an old logging road ('Cavendish Road') from Caira to Albaneta Farm, which had been prepared by engineer units under the cover of darkness, and thence toward the abbey. However, a surprise and fiercely pressed counter-attack from the monastery on Castle Hill by the 1st Fallschirmjägerdivision completely disrupted any possibility of an assault on the monastery from Castle Hill and Hangman’s Hill while the tanks, lacking infantry support, had all been knocked out by the middle of the afternoon. In the town the attackers made little progress, and in overall terms the initiative was passing to the Germans, whose positions close to Castle Hill, he gateway to the position on Monastery Hill, destroyed any prospect of early success.

On 20 March Freyberg committed elements of the 78th Division to the battle, firstly to provide a greater troop presence in the town so that cleared areas would not be re-infiltrated by the Germans, and secondly to reinforce Castle Hill and thus permit the release of troops to close off the two routes between Castle Hill and Points 175 and 165 from being used by the Germans to reinforce the defenders in the town. The Allied commanders felt they were on the brink of success as grim fighting continued through 21 March. However, the defenders were resolute and the attack on Point 445 to block the German reinforcement route had narrowly failed whilst in the town Allied gains were measured only house by house.

On 23 March Alexander met his subordinate commanders. A range of opinions was expressed as to the possibility of victory, but it was evident that the New Zealand 2nd Division and Indian 4th Division were exhausted. Freyberg was convinced that the attack could not continue and he terminated it. The 1st Fallschirmdivision had taken a mauling but had held.

The next three days were spent in the stabilisation of the front, and the extraction of isolated Gurkhas from Hangman’s Hill and of the detachment of New Zealand 24th Battalion which had held Point 202 in similar isolation. The Allied line was reorganised with the exhausted Indian 4th Division and New Zealand 2nd Division withdrawn and replaced respectively in the mountains by the British 78th Division and in the town Brigadier J. C. Haydon’s British 1st Guards Brigade. The New Zealand Corps headquarters was disestablished on 26 March and control was assumed by Lieutenant General S. C. Kirkman’s British XIII Corps. In their time on the Cassino front line the Indian 4th Division had lost 3,000 men and the New Zealand end Division 1,600 men killed, missing and wounded.

The German had also paid a heavy price. The XIV Panzerkorps' war diary for 23 March noted that the battalions in the front line had strengths varying between 40 and 120 men.

The fourth, and as it emerged, final battle for Monte Cassino was part of Alexander’s 'Diadem' strategic offensive to break through the 'Gustav-Linie'. Alexander’s strategy in Italy was to 'force the enemy to commit the maximum number of divisions in Italy at the time the cross-channel invasion [of Normandy] is launched'. Circumstances gave him the time to prepare a major offensive to achieve this. His plan, originally inspired by Juin’s idea to circle around Cassino and take the Aurunci with his mountain troops and thus break the 'Gustav-Linie', was to relocate the bulk of Leese’s British 8th Army from the Adriatic Sea front across the spine of Italy to join Clark’s US 5th Army and attack along a 20-mile (32-km) front between Cassino and the sea. The US 5th Army, in the form of Keyes’s US II Corps and Juin’s Corps Expéditionnaire Français, would be on the left and British 8th Army, in the form of Kirkman’s British XIII Corps and Anders’s Polish II Corps, on the right. With the arrival of better weather with the the spring, ground conditions were improved, and it would be possible to undertake the effective deployment and supply of large infantry and armour formations.

The plan for 'Diadem' was that the US II Corps on the left would attack northward up the western coast along the line of Highway 7 toward Rome. To the US II Corps' right, the Corps Expéditionnaire Français would attack from the bridgehead across the Garigliano river (originally created by the British X Corps in the first battle in January) into the Aurunci mountains, which constituted a barrier between the coastal plain and the Liri river valley. The British XIII Corps in the centre right of the front would attack along the Liri river valley. On the right Polish II Corps (Polish 3rd and 5th Divisions) had relieved the British 78th Division in the mountains behind Cassino on 24 April and would attempt the task which had defeated the Indian 4th Division in February, namely the isolation of the abbey and a drive round behind it into the Liri river valley to link with the XIII Corps' thrust and pinch out the Cassino position. It was hoped that being force considerably larger than its Indian 4th Division predecessor, it would be able to saturate the German defences. As a result, these would be unable to provide supporting fire to each other’s positions. Improved weather, ground conditions and supply would also be important factors. Once again, the pinching manoeuvres by the Polish and British corps were key to the overall success. Lieutenant General E. L. M. Burns’s Canadian I Corps would be held in reserve ready to exploit the expected breakthrough. Once the German 10th Army had been defeated, Major General Lucian K. Truscott’s US VI Corps would break out of its Anzio lodgement and cut off the retreating Germans in the Alban Hills.

The large troop movements required for this change of concept required two months to implement. The movements had to be carried out in small units to maintain secrecy and surprise. Walker’s US 36th Division was sent on amphibious assault training and road signposts and dummy radio signal traffic were created to give the impression that a seaborne landing was being planned for Italy’s western coast in the area to the north of Rome. This was planned to keep German reserves held back from the 'Gustav-Linie'. Movements of troops in forward areas were confined to the hours of darkness, and armoured units moving from the Adriatic Sea front left behind dummy tanks and vehicles so that the vacated areas appeared unchanged to German air reconnaissance. The deception was successful, as as late as the second day of the final Cassino battle, Kesselring estimated the Allies had six divisions facing his four on the Cassino front whereas there were, in fact, 13 divisions.

The first assault of the final 'Battle of Monte Cassino' started on 11 May at 23.00 with a massive artillery bombardment by 1,060 and 600 guns on the 8th Army and 5th Army fronts respectively, and involved British, US, Polish, New Zealander, South African and French units. Within 90 minutes the ground attack was in motion in all four sectors. By the arrival of daylight, the US II Corps had made little progress, but its 5th Army partner, the Corps Expéditionnaire Français, had achieved its objectives and was fanning out in the Aurunci mountains toward the 8th Army on its right, rolling up the German positions between the two armies. On the 8th Army front, the British XIII Corps had made two strongly opposed crossings of the Garigliano river by Major General A. D. Ward’s British 4th Division and Major General D. Russell’s Indian 8th Division. Crucially, the engineers of the Indian 8th Division had by the morning succeeded in bridging the river, enabling the armour of Brigadier W. C. Murphy’s Canadian 1st Armoured Brigade to cross and provide the vital element, so missed by the Americans in the first battle and the New Zealanders in the second battle, to beat off the inevitable counterattacks by German tanks.

In the mountains above Cassino, the aptly named Mt Calvary (Monte Calvario, or Point 593 on Snakeshead Ridge) was taken by the Polish II Corps, only to be recaptured by German paratroopers. For three days, Polish attacks and German counterattacks brought heavy losses to both sides: the Polish II Corps lost 281 officers and 3,503 other ranks in assaults on Oberst Ludwig Heilmann’s 4th Fallschirmjägerregiment, until the attacks were called off. In the early morning hours of 12 May, the Polish infantry divisions were met with 'such devastating mortar, artillery and small-arms fire that the leading battalions were all but wiped out'.

By the afternoon of 12 May, the Gari river bridgeheads were being enlarged despite furious counterattacks, whilst the attritional fighting on the coast and in the mountains continued. By 13 May the Allied pressure was starting to tell. The German right wing began to give way before the 5th Army. The French corps had captured Monte Maio and was now in a position to give material flank assistance to the 8th Army in the Liri river valley against which Kesselring had thrown every available reserve in order to buy time to switch to his second prepared defensive position, the 'Hitler-Linie' some 8 miles (13 km) to the rear. On 14 May Moroccan goumiers, moving through the mountains parallel to the Liri river valley, ground which was undefended because it was not thought possible to traverse such terrain, outflanked the German defence while materially assisting the British XIII Corps in the valley. (In 1943, the goumiers were French colonial troops formed into four Groupements des Tabors Marocains, each comprising three loosely organised tabors (roughly equivalent to a battalion) specialising in mountain warfare. Juin’s corps comprised the Commandement des Goums Marocains with the 1st, 3rd and 4th GTMs) under the command of Général de Brigade Augustin Guillaume and totalling some 7,800 fighting men,approximately the infantry strength as a division, and four more conventional divisions: these latter were Général de Division Joseph de Goislard de Monsabert’s 3ème Division d’Infanterie Algérienne, Général de Division François Sevez’s 4ème Division Marocaine de Montagne, Général de Division André Dody’s 2ème Division d’Infanterie Marocaine and Général de Division Diego Brosset’s 1ère Division Française Libre, otherwise the 1ère Division Motorisée d’Infanterie.)

On 15 May, the British 78th Division, with an armoured brigade under command, came into the British XIII Corps line from reserve passing through the British 4th Division’s bridgehead to execute the turning move to isolate Cassino from the Liri river valley.

On 17 May, Anders led the Polish II Corps in launching its second attack on Monte Cassino. With the Poles under constant artillery and mortar fire from the strongly fortified German positions and with little natural cover for protection, the fighting was fierce and at times hand-to-hand. With their line of supply threatened by the Allied advance in the Liri river valley, the Germans decided to withdraw from the Cassino heights to the new defensive positions of the 'Hitler-Linie'. In the early hours of 18 May the British 78th Division and Polish II Corps linked in the Liri river valley 2 miles (3.2 km) to the west of Cassino town. On the Cassino high ground, the survivors of the second Polish offensive were so battered that 'it took some time to find men with enough strength to climb the few hundred yards to the summit.' A patrol of Polish 12th Podolian Cavalry Regiment finally made it to the heights and raised a Polish flag over the ruins. The only remnants of the defenders were a group of 30 wounded Germans who had been unable to move.

Formations and units of the 8th Army advanced up the Liri river valley and those of the 5th Army up the coast to the 'Hitler-Linie', which was renamed the 'Senger-Linie' at Hitler’s insistence to minimise the significance if it was penetrated. An immediate follow-up assault failed, and the 8th Army then decided to take some time to reorganise. Getting 20,000 vehicles and 2,000 tanks through the broken 'Gustav-Linie' was a major job requiring several days of hard work. The next assault on the line began on 23 May with the Polish II Corps attacking Piedimonte San Germano, which was defended by the redoubtable 1st Fallschirmjägerdivision, on the right and Major General C. Vokes’s Canadian 1st Division, fresh from the 8th Army’s reserve, in the centre. On 24 May, the Canadians had breached the line and Major General B. M. Hoffmeister’s Canadian 5th Armoured Division debouched through the gap. On 25 May the Poles took Piedimonte and the line collapsed. The way was clear for the advance northward on Rome and beyond.

As the Canadians and Poles launched their attack on 23 May, Truscott, who had replaced Lucas as commander of the US VI Corps on 28 February, launched 'Buffalo' as a two-pronged attack using three US and two British divisions of the seven divisions in the lodgement at Anzio. The 14th Army, facing this thrust, was without any armoured divisions because Kesselring had sent his armour south to assist the 10th Army on the Cassino front. A single armoured division, Generalleutnant Smilo Freiherr von Lüttwitz’s 26th Panzerdivision, was in transit from the area to the north of Rome, where it had been held anticipating the non-existent seaborne landing the Allies had faked, and so was currently unavailable.

By 25 May, with the 10th Army in full retreat, Truscott’s US VI Corps was, as planned, driving eastward to cut it off. By the next day the corps would have been astride the German line of retreat and the 10th Army, with all Kesselring’s reserves committed to it, would have been trapped. At this point, astonishingly, Clark ordered Truscott to change his axis of attack from north-east toward Valmontone on Route 6 to north-west directly toward Rome. The rationale for Clark’s decision is unclear, and controversy surrounds the issue. Most commentators point to Clark’s ambition to be the first to arrive in Rome, although some suggest he was concerned to give a necessary respite to his tired troops, notwithstanding the fact that the new direction of attack required his troops to make a frontal attack on the Germans' prepared defences on the 'Cäsar-Linie'. Truscott later wrote that Clark 'was fearful that the British were laying devious plans to be first into Rome', a sentiment somewhat reinforced in Clark’s own writings. However, Alexander had clearly laid down the army boundaries before the battle and Rome was allocated to the 5th Army. The 8th Army was constantly reminded that its task was to engage the 10th Army, destroy as much of it as possible and then bypass Rome to continue the pursuit to the north, which was what the army did, harrying the retreating 10th Army for some 225 miles (360 km) toward Perugia in the following six weeks.

A major opportunity was thus missed and seven divisions of the 10th Army were able to make their way to the next line of defence, the 'Trasimene-Linie', where they were able to link with the 14th Army and then make a fighting withdrawal to the formidable 'Gotisch-Linie' to the north of Florence.

Rome was entered by the 5th Army on 4 June 1944, just two days before the Normandy invasion.

The Allied capture of Monte Cassino had come at a high price. The Allies suffered about 55,000 casualties in the Monte Cassino campaign, and the German casualty figures are estimated at around 20,000 men killed and wounded. The total Allied casualties during the period of the four battles of Monte Cassino and the Anzio campaign, together with the subsequent capture of Rome, were more than 105,000.

The town of Cassino was completely razed by the air and artillery bombardments it had suffered, and most especially by the air attack of 15 March 1944, when 1,250 tons of bombs were dropped on the town, and 2,026 of its pre-war population of 20,000 were killed during the raids and the battle.

In the course of the battles, the ancient abbey of Monte Cassino, where in 516 St Benedict first established the Rule that ordered monasticism in the west, was entirely destroyed by Allied bombing and artillery barrages in February 1944. Some months earlier, in the Italian autumn of 1943, two officers of Generalmajor Paul Conrath’s Panzerdivision 'Hermann Göring', Hauptmann Maximilian Becker and Oberstleutnant Julius Schlegel, proposed the removal of Monte Cassino’s treasures to the Vatican and Vatican-owned Castel Sant’Angelo before the Allies reached Cassino. The officers convinced Catholic church authorities and their own senior commanders to use the division’s trucks and fuel for the undertaking, and first had to find the materials with which to make the necessary crates and boxes, find carpenters among their troops, recruit local labourers (to be paid with rations of food plus 20 cigarettes per day) and then manage the 'massive job of evacuation centred on the library and archive', a treasure 'literally without price'. The richness of the abbey’s archives, library and gallery included '800 papal documents, 20,500 volumes in the Old Library, 60,000 in the New Library, 500 incunabula, 200 manuscripts on parchment, 100,000 prints and separate collections'. The first trucks, carrying paintings by Italian old masters, were ready to go less than one week from the day Becker and Schlegel independently came to Monte Cassino. Each vehicle carried monks to Rome as escorts; in more than 100 truckloads the convoys saved the abbey’s monastic community. The task was completed in the first days of November 1943. 'In three weeks, in the middle of a losing war, in another country, it was quite a feat.' After a mass in the basilica, Abbot Gregorio Diamare formally presented signed parchment scrolls in Latin to Conrath, Schlegel and Becker 'for rescuing the monks and treasures of the Abbey of Monte Cassino'.

The US government’s official position on the German occupation of Monte Cassino changed over a quarter of a century. The assertion that the German use of the abbey was 'irrefutable' was removed from the record in 1961 by the Office of the Chief of Military History. A congressional inquiry to the same office in the 20th anniversary year of the bombing stated that 'It appears that no German troops, except a small military police detachment, were actually inside the abbey' before the bombing. The final change to the US Army’s official record was made in 1969 and concluded that 'the abbey was actually unoccupied by German troops'.