While Britain and Spain had initially entered the French Revolutionary War as allies, in 1796 Spain had switched to supporting France and had gone to war with Britain. The British attempted to assert their authority over the Mediterranean but had a shortage of usable bases. After the failure to establish a British presence in Corsica, other targets such as Menorca, Malta and Elba were considered. Once the French Mediterranean Fleet had been destroyed in Aboukir Bay, Earl St Vincent was determined to restore British hegemony in the Mediterranean. To ensure this, his fleet needed a base with a well protected deep water harbour that could not be assaulted by land. The best island harbour in the Western Mediterranean was at Port Mahon on Menorca, where a large modern dockyard included a careening wharf, extensive storehouses and a purpose-built naval hospital. At the end of October St Vincent decided to send an expedition against Menorca, which departed on 19 October 1798.