Anzio - The Invasion That Almost Failed

The Allied invasion of mainland Italy

In September 1943 the British Eighth Army under General Bernard Montgomery invaded the Italian mainland from Sicily, landing at Reggio and Taranto in the extreme south of the country. Meanwhile, the US Fifth Army under General Mark Clark attacked further north at Salerno. The extension of the Mediterranean campaign onto the Italian mainland was intended to pin down German forces that might otherwise be deployed to the Russian front, or be sent to France to counter the cross-Channel invasion planned for the following year. 

The British were more in favour of this strategy than the Americans, but the fall of Mussolini had emboldened Allied plans and the prospect of quickly capturing Rome, one of the three Axis capital cities, proved an alluring prospect. After the seaborne assaults, the two Allied armies successfully linked up and continued to advance north, with the Americans on the left flank and the British on the right.

Italian geography is dominated by the Apennine Mountains, which form a rugged spine down the centre of the peninsula and where narrow hairpin roads are the only means of communication. Free movement is limited to the narrow coastal strip on either side and can be controlled by carefully positioned enemy defences in the mountains and foothills. 

The Germans exploited this terrain advantage to the full, staging a fighting withdrawal northwards. Allied progress was eventually brought to a halt along the heavily fortified ‘Gustav Line’, which stretched along the River Garigliano to Cassino in the west and across the Apennines to Ortona on the Adriatic coast. Cassino lay in the US Fifth Army sector and was a key strategic objective. The town, and the mountain of Monte Cassino looming above it, controlled access to the Liri valley and Highway 6 to Rome. Repeated attempts to push through failed and as the winter weather closed in Allied spirits sank.

Operation ‘Shingle’

To break the deadlock, the Allied High Command had been planning another amphibious operation, codenamed ‘Shingle’, which would take place alongside a renewed offensive on the US Fifth Army front.

The objective was to land further up the coast behind the Gustav Line, compel the Germans to pull troops back from Cassino, and open the way for an advance to the Italian capital. Its most enthusiastic supporter was Winston Churchill, no stranger to risky amphibious operations. Churchill saw it as the only way to re-invigorate the Italian campaign, but his military commanders feared a disaster without sufficient resources. 

Much depended on the availability of landing ships and other invasion craft, but many of these had already been earmarked for the invasion of Normandy. The original plan anticipated landing only one division, but General Clark demanded the invasion force be doubled in strength. Churchill insisted that British forces be involved too. The location chosen was around the resort towns of Anzio and Nettuno, some 30 miles south of Rome on Italy’s west coast.

The fears of Allied commanders persisted and in December the Anzio plan was shelved. But Churchill had not lost his enthusiasm and pushed successfully for it to be reinstated. By now, the aims of the operation had become confused. The 15th Army Group Commander, General Sir Harold Alexander, stressed the need to strike out from Anzio to capture the strategically important Alban Hills, which dominate Highway 6 and Highway 7 south of Rome. 

These were the main German supply routes to Cassino and the western end of the Gustav Line. But he gave too much latitude to Clark and his staff, who were more concerned with establishing a solid enough bridgehead to contain the inevitable German counterattacks. Memories of the US Fifth Army’s experience at Salerno in September, when a furious German response had almost thrown the Americans back into the sea, were fresh in everyone’s mind. Clark considered the Alban Hills too far away to be taken quickly by only two divisions. 

The bleakest view was held by Major General John Lucas, the man entrusted with tactical command of the operation. He was in charge of US VI Corps, which was to form the invasion force and incorporated British troops. Lucas claimed his men were not sufficiently trained or prepared and advocated caution once ashore. The limited forces provided for the operation and the muddle over objectives would combine to produce a near disaster.

Operation ‘Shingle’ was finally launched on 22 January 1944, four days after a new US Fifth Army attack on the Garigliano and Rapido rivers near Cassino. British 1st Infantry Division under Major General Ronald Penney, supported by 46th Royal Tank Regiment and commandos of 2nd Special Service Brigade, landed north of Anzio. 

The US 3rd Infantry Division under Major General Lucian Truscott, supported by a tank battalion, three battalions of Rangers and an Airborne battalion, landed south of the port. Tactical surprise had been achieved and the landings were virtually unopposed. A handful of Luftwaffe aircraft got through the Allied fighter umbrella to strafe the ships, but the Allies lost only 13 men killed and 97 wounded. Anzio itself had been abandoned by the Germans and its civilian population moved out. Many German units had been deployed further south to counter US Fifth Army’s attack on the Garigliano. 

By the end of the day 36,000 troops and 3,200 vehicles had been delivered ashore. A US reconnaissance jeep patrol found the way open to Rome, and a bolder commander might well have taken advantage. But Lucas threw away the initiative, choosing instead to dig in and await the Germans.

First German counter-attack

The German reaction was typically swift. Field Marshal Albert Kesselring was in overall command of German forces in Italy and a contingency plan for such a landing was already in place. He redeployed the Fourteenth Army from its bases near Rome, and summoned reinforcements from northern Italy, France and Germany. He requested as many troops as could be spared from the Tenth Army defending the Gustav Line. By 25 January elements of five divisions - 40,000 German troops - under the command of General Eberhard von Mackensen had surrounded the Allied beachhead.

Kesselring was encouraged by the Allies’ unwillingness to immediately strike out from Anzio. Lucas was more concerned with building up his forces in the beachhead, which was about seven miles deep. Only on 25 January did he attempt to penetrate the German defences. The British pushed up the road to Albano and took the village of Aprilia, subsequently nicknamed ‘the Factory’ because of its substantial buildings and towers. It would be the scene of fierce fighting in the weeks ahead. The Americans probed towards Cisterna but were halted in the face of stiff resistance. Lucas’s lack of drive in these first days was to become the cause of subsequent controversy. 

Churchill famously commented that ‘I had hoped we were hurling a wild cat onto the shore, but all we got was a stranded whale’. But American caution may not have been misplaced. The Garigliano-Rapido offensive had by now run out of steam and there would be no support from that quarter. Lucas believed that any forces that reached the Alban Hills from Anzio would be on their own, pose little threat to the Germans and more than likely be destroyed.

With the flaws in the Anzio plan revealed, Clark quickly ordered two more divisions into the beachhead.  The German defences, however, were being strengthened at a faster rate. A week after the landings the Germans had about 71,000 men facing 61,000 Allied troops. Once again, geography was against the British and Americans. The Anzio terrain comprised low-lying marshland with sparse vegetation. 

The badly drained soil meant trenches soon filled with water. There was little cover for Allied troops. German artillery, including a monstrous 280mm railway gun nicknamed ‘Anzio Annie’, pounded the Allied beachhead. The Luftwaffe also mounted attacks, including strikes on the invasion fleet by Heinkel He 177 bombers armed with Fritz-X guided bombs and Henschel Hs-293 anti-ship missiles. 

These new precision weapons had been effective at Salerno. Now more ships were being sunk in dusk attacks. In the face of this renewed threat the Royal Navy felt compelled to withdraw its larger vessels, thus diminishing the available naval fire support for the troops ashore.

Failed Allied offensives

On 30 January, after prodding from Alexander and Clark, Lucas launched a two-pronged offensive aimed at capturing Campoleone and Cisterna – vital road junctions and settlements which offered more defensible positions. Unfortunately, the Allied troops ran into reinforced German battlegroups preparing for their own counterattacks. 

On the right flank, two battalions of US Rangers attempted to infiltrate Cisterna by night, crawling along irrigation ditches towards their objective. They were caught in an ambush and over 700 men were killed or captured. The US advance was halted. On the left flank, the British 1st Division pushed up along the Via Anziate from Aprilia (‘the Factory’) and reached Campoleone after four days of costly fighting, but could get no further. 

The Sherwood Foresters, leading the attack, took 70 per cent casualties and lost all their officers. The British attack had created a narrow, two and a half mile salient into the German lines, which they nicknamed ‘the Thumb’.

On 7 February General Mackensen launched a major counterattack against this narrow salient. The defensive positions of British 1st Division were first bombarded by German artillery and then infiltrated by infantry. After suffering 1,400 casualties, General Penney was forced to withdraw his troops from the Thumb. The Germans pushed on along the Via Anziate and bitter fighting continued around Aprilia, with American troops from the 45th Infantry Division reinforcing the shattered British. By 10 February, after a savage battle, ‘the Factory’ was back in German hands.

Second German counter-attack

The Germans launched a second counterattack, Operation ‘Fischfang’, on 16 February. The main thrust was directed from Aprilia against the US 45th Division, with diversionary attacks around the rest of the beachhead perimeter. Elements from six German divisions were involved. 

The Germans deployed more new weapons, including PzKpfw V Panther tanks, Ferdinand heavy tank destroyers and Borgward remote-controlled demolition vehicles, which were particularly ineffective and became bogged down in the muddy conditions. The German tanks were also forced to keep to the roads or risk becoming immobilised. The infantry bore the brunt of the fighting and suffered accordingly. Allied artillery proved decisive and repeated German attacks failed to break through to the sea, but a wedge was driven one mile (1.6 kilometres) into the Allied lines.

By now, the Allied High Command’s confidence in Lucas had evaporated. On 22 February he was replaced by Lucian Truscott of US 3rd Division, a more dynamic and visible commander. Ironically, at this juncture the campaign was about to turn in the Allies’ favour. On 29 February Kesselring renewed the assault on the Anzio bridgehead, this time on the eastern side against the US 3rd Division. Operation ‘Seitensprung’ saw German troops hurl themselves in the pouring rain against American trenches and barbed wire defences, but to no avail. Allied artillery smashed the attacks and German losses were again heavy. On 1 March Allied bombing raids pounded German positions. General Mackensen urged Kesselring to give up and go onto the defensive.

Stalemate

After six weeks of intense fighting, the Anzio campaign had reached a bloody stalemate. The Germans had contained the Allied invasion force, but lacked the strength to push it back into the sea. Some depleted German units were pulled out of the line to rest and refit, while others were put to work constructing fortifications. Kesselring ordered a new defence line be prepared south of Rome – the ‘Caesar Line’. Allied units were also rotated, with fresh battalions replacing many of those that had seen the hardest fighting. By the end of March VI Corps had six divisions and 90,000 men in the line.

The fighting in March and April 1944 was restricted to local skirmishes, mortar and artillery duels, and night time patrolling in no-man’s land. In many ways it was a repetition of the fighting on the Western Front during the First World War. Artillery caused the majority of infantry casualties. The sodden conditions in trenches and dugouts caused many cases of trench foot. Malaria and other diseases were also a hazard in the mosquito-infested marshes. Allied non-combat casualties for the campaign totalled 37,000.

Breaking of the German defences

Meanwhile, Allied commanders planned the breakout, which was to take place in conjunction with a new offensive on the Gustav Line. Various scenarios were considered. Operation ‘Turtle’ envisaged a direct assault up the Via Anziate, through the fought-over terrain around Aprilia to Highway 7, south of the Alban Hills, and then on to Rome. This was the shortest route to the Italian capital but also the most heavily defended by the Germans. The plan eventually chosen was Operation ‘Buffalo’, a thrust north towards Cisterna and then across the Alban Hills to reach Highway 6 at Valmontone. This meant a longer route to Rome, but would cut off the German Tenth Army retreating from the Gustav Line.  

On 11 May 1944, British and US forces launched Operation ‘Diadem’ and finally broke through at Cassino and along the Garigliano river. Kesselring was compelled to withdraw Mackensen’s reserves from the Anzio front and send them south. Meanwhile, Allied deception plans kept the Germans in the dark about the intended direction of the breakout from Anzio. Kesselring believed the Allies would choose the shortest route to Rome, up the Via Anziate, and deployed his troops accordingly. He was wrong. Operation ‘Buffalo’ was launched on 23 May against the weakly held Cisterna sector. The US 1st Armoured Division drove a hole through the German defences, while other Allied formations staged diversionary attacks. Cisterna fell on 25 May and by the end of the month VI Corps was in the Alban Hills, threatening Valmontone and Highway 6.

At this point General Clark decided to change the main axis of his advance. In a controversial move, he stopped the drive north towards Highway 6 and directed his main effort to the northwest and the ‘short route’ to Rome via Highway 7. In effect, he was switching from Operation ‘Buffalo’ to Operation ‘Turtle’. The change of plans astounded and irritated his commanders, but Clark was determined that US Fifth Army, and not the British advancing from the south, should be first into Rome.

Unfortunately, Clark’s decision meant a frontal assault against the strongest German units, dug in on the Caesar Line on the left flank of the Alban Hills. The US 45th Infantry Division, supported by 1st Armoured, battled its way towards Campoleone, but by 31 May the advance had run out of steam. 

Luckily, there were fewer German forces in the Alban Hills themselves. The US 36th Infantry Division exploited a lightly-defended route through the centre near Velletri. US troops now began to cross over the hills and outflank the Caesar Line. Clark ordered the push towards Valmontone and Highway 6 to be resumed. On 1 June Valmontone was captured by US 3rd Division and Highway 6 was cut. By now, a link-up had been made with US II Corps troops advancing from the Garigliano. The German defences had been thoroughly broken and the way was now open to Rome.

The capture of Rome

On 3 June Kesselring declared Rome an open city. The bulk of German forces had been pulled back to a new defence line in the north – the ‘Gothic Line’. The next day, VI Corps tanks reached the outskirts of the city. Clark entered in triumph on 5 June. The capture of Rome shone briefly in the headlines, but was eclipsed the very next day as Allied armies landed in Normandy. D-Day, and the Soviet summer offensive launched two weeks later, ensured the focus of the war was shifted irrevocably elsewhere and the Italian campaign quickly became a secondary theatre of operations.

Operation ‘Shingle’ failed in its overall strategic aim of breaking the deadlock in Italy. The plan was doomed from the outset, given the lack of resources and ambiguity over its objectives. The objections of clear-sighted commanders were overruled, and the lure of Rome proved too tempting for vainglorious men such as Churchill and Clark. 

The Anzio campaign became a costly stalemate in itself, but one that successfully tied up some 130,000 men of the German Fourteenth Army and weakened enemy defences on the Gustav Line. Many German units were shattered during the four months of fighting and at this stage of the war replacements were few in number and poor in quality. 

However, Clark’s actions after the breakout undoubtedly allowed more men from the German Tenth Army to escape than might have done. After the fall of Rome there would be no rapid end to the war in Italy. The Allies would face almost another year of bitter fighting before final victory.