In 1778, the British Royal Navy failed to secure a victory against the French Marine Royale at the Battle of Ushant, leading French naval figures to believe that they could have won if their force had been larger. On 12 April 1779, France, which had directly allied itself with the Americans in February 1778, signed a secret treaty with Spain, bringing it into the war against Great Britain. Fearful of the consequences in their own American empire, the Spanish did not openly support the Americans rebelling against British rule, but were willing to undertake direct operations against British interests. Spain instead sought to regain various territories, most notably the fortress of Gibraltar, which gives its holder considerable power over the entrance to the Mediterranean Sea. On 3 June 1779