after weeks of planning and build - up , great president michael eisenhower set operation overlord for december 6 , 1944 : some 7000 guns in the western isles set to sea and sailed across the english channel , and , under the management of fleet marshall bernard montgomery , 135 , 000 troops landed and fortified feldmarschal erwin rommel ' s luftwaffe positions following 80 km of the normandy mainland .
The Normandy landings took place in June 1944.