The breakout from the Anzio beachhead

At 5.45 a.m. on 23 May 1944 some 1,500 Allied guns opened fire on the German positions around the beachhead at Anzio. An hour later the infantry and tanks of the US VI Corps moved off to attack Cisterna. This was the start of Operation Buffalo – the breakout from a beachhead where the Allies had been hemmed in by the German Fourteenth Army for four months, since the Anzio landing of 22 January. The attack was meant to cut the line of retreat of the German Tenth Army, which was falling back from Cassino after losing the battle for the Gustav Line.

The attack began just as the Allies’ spring offensive in Italy was entering its second phase. That same day the British Eighth Army attacked the Hitler Line in the Liri valley, while French and American units of the Fifth Army pushed north through the mountains and along the coast. The first day of the breakout proved one of the bloodiest of the entire Italian campaign, but after four months of positional warfare the German ring around the beachhead began to crack.

The beachhead before the offensive

After the failure of the German offensive at the turn of February and March, the Germans went over to the defensive at Anzio and the beachhead fell quiet. Through April and May both sides patrolled, exchanged artillery fire and rebuilt their battered units. VI Corps, commanded since 23 February by Major General Lucian Truscott, successor to the dismissed John Lucas, grew stronger thanks to convoys from Naples. By the end of May, according to most accounts, there were about 150,000 Allied troops in the beachhead: Major General Ernest Harmon’s US 1st Armored Division, Brigadier General John O’Daniel’s 3rd Infantry Division, the 34th and 45th Infantry Divisions, the 36th Infantry Division, which arrived in May, Brigadier General Robert Frederick’s American-Canadian 1st Special Service Force, and the British 1st and 5th Infantry Divisions.

Facing them was General Eberhard von Mackensen’s Fourteenth Army, with I Parachute Corps on the western and LXXVI Panzer Corps on the eastern sector of the perimeter. The five divisions in the front line – the 4th Parachute, the 65th and 362nd Infantry Divisions, the 3rd Panzergrenadier Division and the 715th Infantry Division – were well dug in but short of officers and NCOs. Field Marshal Albert Kesselring had kept his best units, including the 26th Panzer Division and the 29th Panzergrenadier Division, in reserve, or in May had sent them south, where the Tenth Army was fighting. Behind the beachhead the Germans were building the Caesar Line, which ran across the Alban Hills south of Rome.

The Buffalo plan and the dispute over the objective

The breakout was part of Operation Diadem, the spring offensive of General Harold Alexander’s whole 15th Army Group. On the evening of 11 May General Oliver Leese’s Eighth Army and General Mark Clark’s Fifth Army attacked the Gustav Line. After several days of heavy fighting the front on the Gari was broken, the French corps crossed the Aurunci Mountains, and on 18 May soldiers of the Polish II Corps took Monte Cassino. General Heinrich von Vietinghoff’s German Tenth Army was falling back to the Hitler Line, and VI Corps was to strike at its rear.

On Clark’s instructions Truscott’s staff prepared four variants of the attack. Buffalo envisaged a thrust through Cisterna and on between the Alban Hills and the Lepini Mountains towards Valmontone, on the Via Casilina – Highway 6, the Tenth Army’s main route of supply and retreat. Turtle provided for an attack west of the Alban Hills, through Campoleone and Albano, straight on Rome. On 5 May Alexander chose Buffalo and issued Clark with the corresponding orders. His intention was to trap as much of the Tenth Army as possible between the forces advancing from the south and VI Corps.

Clark thought differently from the start. He believed that VI Corps was not strong enough to stop the whole retreating army, since the Germans had many other escape routes through the valley and the mountains, and he wanted Rome to be taken by his Fifth Army. In his memoirs he wrote openly that his soldiers not only wanted the honour of capturing Rome but felt they had earned it. According to British and American historians, Alexander, instead of making matters plain, was conciliatory towards Clark and left him with the impression that a drive on Rome was possible if difficulties arose. On 6 May Clark wrote to Truscott that “the capture of Rome is the only important objective” and told him to be ready to carry out either Buffalo or Turtle.

Truscott planned the attack carefully. On the left flank the British 1st and 5th Divisions were to attack along the coast and the Anzio–Albano road to pin down the 4th Parachute Division, the 65th Infantry Division and the 3rd Panzergrenadier Division opposite them. The main blow, on a front of a dozen or so kilometres, was to be delivered by the 45th Division, the 1st Armored Division and the 3rd Division: the Americans were to surround and take Cisterna, cut the railway and Highway 7 (the Via Appia), and then advance through the gap near Cori towards Valmontone. The right flank, facing the Pontine Marshes, was covered by the 1st Special Service Force. The 34th Division was to tie down the enemy in its sector, and the 36th Division was held in reserve. The timing depended on Alexander, who was waiting for the Tenth Army to begin withdrawing from Cassino; in the end VI Corps was to move on the morning of 23 May, simultaneously with the Eighth Army’s attack on the Hitler Line.

23 May: the attack on Cisterna

The bombardment began at 5.45 a.m. and lasted about forty minutes. When the guns fell silent, aircraft appeared over the German positions: light bombers attacked Cisterna and fighter-bombers strafed the gullies south of the town. At 6.25 a.m. the infantry and tanks went forward, and the artillery again lifted its fire deeper into the German defences. The 45th Division attacked on the left of the assault, the 1st Armored Division in the centre, and the 3rd Division, with supporting tank and tank-destroyer battalions, went for Cisterna itself. The British on the left flank attacked along the Albano road and on the Moletta river so violently that for the next two days Mackensen was convinced the Allied main effort lay there, and kept his reserves in that sector.

The fighting was very hard from the outset. Cisterna was the same town before which, at the end of January, two battalions of American Rangers had been killed or captured in a failed attack. The Germans had turned every house, railway embankment and drainage ditch on the plain in front of Cisterna into a strongpoint, and they had been extending their minefields for months. The 1st Armored Division forced its way through them at the cost of about a hundred tanks and tank destroyers, mostly damaged or destroyed on mines, but by evening it had cut the railway and reached Highway 7 north-west of Cisterna. The 3rd Division advanced more slowly, fighting for individual farmhouses and machine-gun posts, and began to work round the town on both sides. On the right flank the 1st Special Service Force reached the area of Highway 7 east of Cisterna, where it beat off German counter-attacks for the rest of the day.

According to the US official history (Anzio Beachhead, American Forces in Action series, 1947), the 3rd Division lost about 950 men killed, wounded and missing that day – more than any other unit on the front; later accounts also cite a figure of 955 and the view that it was the highest one-day loss of any American division in the war. The same history states that on 23 May American forces in Italy lost a total of 334 killed, 1,513 wounded and 81 missing, the highest daily toll of the whole Italian campaign. Almost 1,500 Germans were taken prisoner, half of them in the 3rd Division’s sector. According to American estimates, the 362nd Infantry Division, which defended Cisterna, had lost half its fighting value by evening, and two regiments of the 715th Division had been badly mauled.

Throughout 24 May VI Corps widened the breach. The 1st Armored Division pushed north towards Velletri and the gap leading to Valmontone, while the 3rd Division encircled Cisterna. Kesselring, who, unlike Mackensen, correctly read that the Americans were making for Highway 6, ordered the Hermann Göring Parachute Panzer Division, resting near Livorno, to move to Valmontone. The division had to travel about 240 kilometres, much of it by day, under attack from Allied aircraft, which commanded the skies and had since March been destroying roads and railways in central Italy under Operation Strangle. Its units reached the battlefield piecemeal.

The Hitler Line and the attack from the south

The breakout coincided with the decisive attack on the southern front. After the loss of Monte Cassino the Tenth Army manned the Hitler Line, which ran from Monte Cairo through Piedimonte San Germano, Aquino and Pontecorvo towards the Aurunci Mountains; at Hitler’s wish it had already been renamed the Senger Line, after the commander of XIV Panzer Corps, so that its possible loss would not damage the Führer’s prestige. On the morning of 23 May, after a heavy artillery preparation, the Eighth Army’s I Canadian Corps attacked it. Major General Chris Vokes’s 1st Canadian Infantry Division attacked with two brigades between Pontecorvo and Aquino. The 2nd Brigade on the right came under fire from anti-tank positions, including Panther tank turrets set in concrete emplacements, and according to Canadian figures lost 543 men that day – 162 killed, 306 wounded and 75 taken prisoner – the heaviest loss of any Canadian brigade in a single day of fighting in Italy. The 3rd Brigade on the left, however, broke through the defences, and the next day the 5th Canadian Armoured Division passed through the gap and on 24 May itself seized bridgeheads over the Melfa river.

To the right of the Canadians the Poles, after taking the monastery, attacked Piedimonte, which they captured on 25 May, closing out the last bastion at the northern end of the line. In the south, General Alphonse Juin’s French Expeditionary Corps, which in mid-May had broken the Gustav Line in the Aurunci Mountains, was advancing across the trackless Ausoni Mountains and outflanking the Hitler Line from the south, fighting for Pico. Along the coast the US II Corps pushed through Fondi and on 24 May entered Terracina, from where it was not far across the Pontine Marshes to the beachhead. The German front from the Tyrrhenian Sea to the Apennines began to fall apart, and the Tenth Army, threatened from the south and from the direction of Anzio, began to retreat northwards.

Place in the war

Operation Buffalo was the moment when the Anzio landing – long regarded as a costly failure – began to deliver what had been expected of it. For four months the beachhead had tied down the German Fourteenth Army, and in May it became the second arm of a pincer meant to trap the Tenth Army between Cassino and Rome. The first two days of the attack cost VI Corps dearly, but the German defences around the beachhead, built up since February, cracked within two days.

On 25 May the 3rd Division took the ruins of Cisterna in house-to-house fighting, and on the morning of the same day patrols from the beachhead met units of II Corps coming up from the south near Borgo Grappa – the Anzio beachhead was no longer a cut-off enclave. That same day the spearheads of the 1st Armored Division stood a few kilometres from Valmontone. At this point, however, Clark switched the direction of VI Corps’ main thrust to the north-west, towards Rome, and the German Tenth Army, covered at Valmontone and Velletri, withdrew to the Caesar Line and further north. That decision remains one of the most controversial in the history of the Italian campaign. On 4 June the Americans entered Rome, two days before the Allied landings in Normandy.

For the Germans the breakthrough at Anzio and on the Hitler Line meant the end of the defence south of Rome and a long retreat all the way to the Apennines, but not the destruction of Kesselring’s forces. Both German armies kept their fighting capacity and in the autumn of 1944 halted the Allies on the Gothic Line. For the soldiers of VI Corps, 23 May remained the hardest day of the whole Italian campaign – the day on which they paid for four months of siege on the Anzio plain and for breaking out of it.