In May 1944, XIII Corps, now commanded by Sidney Kirkman, was shifted to the left-centre of the Allied front. During the Fourth Battle of Monte Cassino XIII Corps elements, composed of the British 6th Armoured Division, British 4th Infantry Division and 8th Indian Infantry Division with supporting fire from the 1st Canadian Armoured Brigade, made a successful strongly opposed night crossing of the Garigliano and Rapido rivers, and broke into the heart of the German defenses in the Liri valley. This victory was of enormous significance as it collapsed or bypassed the German defenses of Gustav Line and led to the capture of Rome.