Having lost its colonial empire, France saw a good opportunity for revenge against Britain in signing an alliance with the Americans in 1778, and sending an army and navy that turned the American Revolution into a world war. Spain, allied to France by the Family Compact, and the Dutch Republic also joined the war on the French side. Admiral de Grasse defeated a British fleet at Chesapeake Bay while Jean-Baptiste Donatien de Vimeur, comte de Rochambeau and Gilbert du Motier, Marquis de Lafayette joined American forces in defeating the British at Yorktown. The war was concluded by the Treaty of Paris (1783); the United States became independent. The British Royal Navy scored a major victory over France in 1782 at the Battle of the Saintes and France finished the war with huge debts and the minor gain of the island of Tobago.