The Battle of Anzio was a major battle of the Italian campaign of World War II that was fought from January to June 1944. The Allied Powers launched Operation Shingle to outflank the German Winter Line with an amphibious assault on Lazio, which would also enable the Allies to liberate the Italian capital of Rome.
In December 1943, as the Allied advance up the boot of Italy was halted by the German defenses of the Gustav Line, British Prime Minister Winston Churchill conceived a landing at Anzio that would bypass Axis forces in central Italy and take Rome. The initial plan, which would involve the US 3rd Infantry Division landing at Anzio to divert German troops from Monte Cassino, was cancelled due to the risk of the 3rd Division being annihilated. The final plan called for Major General John P. Lucas to lead the VI Corps in a landing at Anzio, followed by an advance into the Alban Hills to cut German communications and threaten the rear of the XIV Panzer Corps, which would draw German forces away from Monte Cassino and facilitate an Allied breakthrough.
Task Force 81, consisting of 40,000 troops and 5,000 vehicles, would land British forces north of Anzio at the Tor San Lorenzo and the Americans at Nettuno, another resort town. As a 16 January 1944 attack on Monte Cassino resulted in the German general Albert Kesselring transferring the 29th Infantry Division and 90th Panzergrenadier Division to Monte Cassino from Rome, the Allies initiated their surprise assault six days later. The initial landings faced light resistance, with 36,000 soldiers and 3,200 vehicles landing on the beaches and securing their objectives at a cost of 13 dead and 97 wounded. The British 1st Infantry Division pushed 2 miles inland and took Aprilia, while the US Army Rangers captured Anzio's port, the US 509th Parachute Infantry Battalion took Nettuno, and the US 3rd Infantry Division penetrated 3 miles inland and probed towards Acciarella and Cisterna.
While the Allied plan involved an immediate rush from the beachhead towards Rome via the Alban Hills, the cautious Lucas instead decided to strengthen the beachhead's defenses and pour more men and material into his positions. This gave Kesselring time to transfer three divisions from France, Yugoslavia, and Germany to prepare a counterattack against the beachhead. All reserves from the southern front, including the 3rd Panzergrenadier Division, 71st Infantry Division, and Hermann Goering Division, were sent to block the Allied advance; by 24 January, the Germans had over 40,000 troops in prepared defensive positions.
By 29 January, the Allies had assembled 69,000 troops, 508 guns, and 208 tanks on the bridgehead, facing 71,500 Germans. The Americans initiated a two-pronged attack on 30 January, the day before a German counterattack was supposed to take place. The American attack on Cisterna resulted in disaster, as lightly-armed US Army Rangers attacked the gathering point for German forces massing for the offensive. The 3rd Infantry Division was unable to break through to Cisterna, while the British 1st Infantry Division failed to breach the German defenses at Campoleone.
By early February, the German 14th Army numbered some 100,000 troops organized into the 1st Parachute Corps and the LXXVI Panzer Corps. Allied forces had risen in number to 76,400. The Germans launched a counterattack on 4 February to reduce the Campoleone salient, shattering the British front line. The 1st Battalion, Irish Guards was reduced to one company, while the 6th Battalion, Gordon Highlanders lost three complete companies as prisoners. The 2nd Battalion, Sherwood Foresters, 1st Battalion, King's Shropshire Light Infantry, and 1st Battalion, Duke of Wellington's Regiment were trapped in a pocket near Campoleone and suffered heavy losses before making a fighting retreat to Aprilia. By 10 February, the Allies were pushed out of the salient, and an Allied counterattack was repulsed on 11 February.
On 16 February, the Germans launched their Operation Fischfang counteroffensive, which initially achieved great success before Allied air and artillery superiority turned the attack three days later. By 22 February, the VI Corps was able to retake lost ground and return to the offensive; by then, the Germans had lost 5,389 men killed, wounded, and missing during their five-day counterattack. 3,496 Allied soldiers had been killed, wounded, or missing, while 1,637 were injured by trench foot, exposure, and combat exhaustion. By 12 February, 96,401 Allied soldiers held a 35-mile perimeter against ten German divisions numbering 120,000 troops.
The Germans resumed their attack on the Anzio beachhead on 29 February, focusing on the German 3rd Infantry Division. The LXXVI Panzer Corps attacked towards Carano and Isola Bella, but the new Allied commander, Lucian Truscott, reinforced the line with additional artillery. The Allies returned 20 shells for each one fired by the Germans, and well-entrenched Americans shattered German attacks over the next several days. The final five-day German counterattack cost 3,500 men killed, wounded, and missing, plus 30 tanks destroyed. The Germans were permanently forced on the defensive, but both sides' exhaustion led to a three-month lull after the German offensive was fought off on 4 March. By 15 March, the German 14th Army had been reinforced to 135,698 troops, but Kesselring decided to conserve troop strength to counter an expected Allied spring offensive. At the same time, British divisions were swapped out and Allied commando, ranger, and parachute units were sent to England to prepare for Operation Overlord. By 22 May, the Allied strength at Anzio reached seven full divisions. German air and artillery attacks inflicted losses on the Allies from March to early May 1944, with the famous "Anzio Annie" (or "Anzio Express") railway gun causing 83% of all 3rd Division casualties in March 1944.
On 11-12 May, the Allies launched their long-awaited spring offensive against the Gustav Line, with the Poles forcing the Germans to abandon Monte Cassino, thus enabling the French Expeditionary Corps and US II Corps to break the Gustav Line by 15 May and capture Terracina on 24 May. German resistance crumbled as their forces withdrew northeast toward Rome. On 5 May, General Mark W. Clark ordered General Truscott to carry out "Operation Buffalo" to break out of the beachhead on the Cisterna front at Cori, at the base of the Lepini Mountains, and at Velletri near the base of the Alban Hills. On 23 May, the Allies launched their offensive, capturing Cisterna on 25 May at a cost of 476 Americans killed, 2,321 wounded, and 75 missing. However, the US 1st Armored Division lost 100 vehicles in the first day alone. The Allies suffered 4,000 casualties in the first five days of the offensive, but they took 4,838 German prisoners and destroyed or damaged 2,700 German vehicles. The Allies ultimately failed to encircle the retreating Germans, and the Allies pursued the Germans to Rome, just 30 miles to the north. Allied forces liberated Rome on 4 June 1944, having lost 29,200 men (4,400 killed, 18,000 wounded, and 6,800 prisoners) during the four months of the Anzio campaign. The Germans had lost 27,500 (5,500 killed, 17,500 wounded, and 4,500 prisoners or missing).
While Operation Shingle failed to outflank the Gustav Line, restore mobility to the Italian campaign, or speed the capture of Rome, it forced the Germans to surrender their initiative by paying attention to a new Allied threat, and the German 14th Army was prevented from making the Gustav Line impregnable. The Germans proceeded to withdraw to the Gothic Line north of Rome, condemning the Allies to another year of bloody combat from August 1944 to March 1945.