Complex sentence: The battalion fought in the Allied invasion of Italy and the Battle of Arnhemwhere its heavy casualties resulted in the disbandment of the battalion, the surviving men being distributed amongst the battalions of the 1st Parachute Brigade.
Split into simpler sentences: The battalion fought in the Allied invasion of Italy and the Battle of Arnhem. The surviving men being distributed amongst the battalions of the 1st Parachute Brigade.