Before the Allied forces could advance into northern France, the 1st British Corps had to occupy Caen. The city, as the centre of an extensive railway network and location of several ammunition and fuel depots, was a key position for the German defence of Normandy. The 1st British Corps, which included the 3rd Canadian Division, launched its assault on the city on 8 July 1944. Royal Air Force and Royal Canadian Air Force attacks that occurred during the night of 7-8 July had prepared the way for this operation. The German defenders contested every street, but, by 9 July 1944, the British and Canadian troops had taken the city.