Complex sentence: After the Battle of the Bulge, McAuliffe was given command of his own division, the 103rd Infantry Division of the US 7th Army, which he led from January 15,1945 to July, 1945.
Split into simpler sentences: After the Battle of the Bulge was over, McAuliffe was given command of his own division, the 103rd Infantry Division (United States) of the US 7th Army. He led the division from January 15,1945 to July, 1945.