In 1940, when Italy entered World War II, the Royal Navy was badly overstretched, and its Mediterranean Fleet had to face both the Italian Navy and the German and Italian Air Forces in a battle for supremacy. Although the British and Italian battle fleets squared off against each other, they were both often held in reserve, in case the enemy fleet put to sea. So, it was left to the cruisers to wage their own naval war in the Mediterranean. This involved a range of missions, from escorting convoys and hunting enemy ones, to fighting for control of the sea around key locations such as the waters off Malta and Crete.