The Battle of Anzio was a battle of the Italian Campaign of World War II that took place from January 22, 1944 (beginning with the Allied amphibious landing known as Operation Shingle) to June 5, 1944 (ending with the capture of Rome). The operation was opposed by German forces in the area of Anzio and Nettuno.
The operation was initially commanded by Major General John P. Lucas, of the U.S. Army, commanding U.S. VI Corps with the intent to outflank German forces at the Winter Line and enable an attack on Rome.
The success of an amphibious landing at that location, in a basin consisting substantially of reclaimed marshland and surrounded by mountains, depended on the element of surprise and the swiftness with which the invaders could build up strength and move inland relative to the reaction time and strength of the defenders. Any delay could result in the occupation of the mountains by the defenders and the consequent entrapment of the invaders. Lieutenant General Mark W. Clark, commander of the U.S. Fifth Army, understood that risk, but he did not pass on his appreciation of the situation to his subordinate Lucas, who preferred to take time to entrench against an expected counterattack. The initial landing achieved complete surprise with no opposition and a jeep patrol even made it as far as the outskirts of Rome. However, Lucas, who had little confidence in the operation as planned, failed to capitalize on the element of surprise and delayed his advance until he judged his position was sufficiently consolidated and he had sufficient strength.
While Lucas consolidated, Field Marshal Albert Kesselring, the German commander in the Italian theatre, moved every unit he could spare into a defensive ring around the beachhead. His artillery units had a clear view of every Allied position. The Germans also stopped the drainage pumps and flooded the reclaimed marsh with salt water, planning to entrap the Allies and destroy them by epidemic. For weeks a rain of shells fell on the beach, the marsh, the harbour, and on anything else observable from the hills, with little distinction between forward and rear positions.
After a month of heavy but inconclusive fighting, Lucas was relieved and sent home. His replacement was Major General Lucian Truscott, who had previously commanded the U.S. 3rd Infantry Division. The Allies broke out in May. But, instead of striking inland to cut lines of communication of the German Tenth Army's units fighting at Monte Cassino, Truscott, on Clark's orders, reluctantly turned his forces north-west towards Rome, which was captured on June 4, 1944. As a result, the forces of the German Tenth Army fighting at Cassino were able to withdraw and rejoin the rest of Kesselring's forces north of Rome, regroup, and make a fighting withdrawal to his next major prepared defensive position on the Gothic Line.
Background
At the end of 1943, following the Allied invasion of Italy, Allied forces were bogged down at the Gustav Line, a defensive line across Italy south of the strategic objective of Rome. The terrain of central Italy had proved ideally suited to defense, and Field Marshal Albert Kesselring took full advantage.
Operation Shingle was originally conceived by British Prime Minister Winston Churchill in December 1943, as he lay recovering from pneumonia in Marrakesh. His concept was to land two divisions at Anzio, bypassing German forces in central Italy, and take Rome, the strategic objective of the current Battle of Rome. By February he had recovered and was badgering his commanders for a plan of attack, accusing them of not wanting to fight but of being interested only in drawing pay and eating rations. General Harold Alexander, commander of the Allied Armies in Italy, had already considered such a plan since October using five divisions. However, the 5th Army did not have the troops nor the means to transport them. Clark proposed landing a reinforced division to divert German troops from Monte Cassino. This second landing, however, instead of failing similarly, would hold "the shingle" for a week in expectation of a breakthrough at Cassino, and so the operation was named Shingle.