In January 1944, the division assaulted Anzio as part of the U.S. VI Corps, which also included the British 1st Infantry Division, along with two British Commandos and three battalions of U.S. Army Rangers, Combat Command B of the 1st Armored Division and the 504th Parachute Regimental Combat Team. The operation, the brainchild of British Prime Minister Winston Churchill, was intended to outflank, and potentially force the Germans to withdraw from their Winter Line defenses, which had considerably slowed Allied progress in Italy.