On 4 December Penney's division departed North Africa for Italy and arrived there three days later, originally to reinforce Montgomery's Eighth Army. However, it was soon transferred to Lieutenant General Mark W. Clark's American Fifth Army, coming under the command of Major General John P. Lucas's US VI Corps, in preparation for Operation Shingle. By December 1943 the Allied Armies in Italy (AAI), consisting of the American Fifth and British Eighth Armies, commanded by General Alexander, were bogged down in front of the Winter Line defences, 80 miles south of Rome. Operation Shingle, General Alexander envisioned, would land Lucas's Anglo-American VI Corps in an amphibious operation at the port town of Anzio, behind the German line, which ran from Monte Cassino to the mouth of the River Garigliano, and draw off German defenders from the Winter Line to face the new threat at Anzio, enabling elements of Clark's Fifth Army to break through at Cassino, drive up through the Liri valley and link up with VI Corps at Anzio. Penney's division was to come under the command of Lucas's US VI Corps, which also included the US 1st Armored and 3rd Infantry Divisions (under Major Generals Ernest N. Harmon and Lucian Truscott, respectively), supported by British Commandos and US Army Rangers, the 504th Parachute Regimental Combat Team (504th PRCT), along with elements of the British 23rd Armoured Brigade, and the operation was to take place on 22 January 1944.