On March 17, 1778, four days after a French ambassador informed the British government that France had officially recognized the United States as an independent nation by signing the Treaty of Friendship and Commerce and the Treaty of Alliance, Britain declared war on France, thereby involving that nation in the American War of Independence.  Entry into the French war would lead to a further escalation of the war when Spain entered the fighting. against Great Britain, an ally of France, after the signing of the Treaty of Aranjuez on 12 April 1779 and again in December 1780, when Great Britain declared war on the Dutch Republic after seizing a Dutch merchant ship which they claimed was carrying contraband to France during the Fielding and Bylandt affair.  Franco-American Alliance, (6) February 1778), France`s agreement to provide military aid and urgent loans to the 13 insurgent American colonies, often seen as a turning point in the American War of Independence. France, furious at the loss of its North American empire after the French and Indian War, welcomed the opportunity to undermine Britain`s position in the New World. The Revolutionary Diplomatic Correspondence of the United States also contains a large collection of letters sent by the American diplomatic team that negotiated the alliance contract with France, Benjamin Franklin, Silas Deane and Arthur Lee. For example, on February 8, 1778, Franklin and Deane sent a letter to Congress announcing the signing of the Alliance and the Treaty of Amity and Commerce. Washington`s initial plan was to use combined American and French forces to drive the British out of New York and its surroundings. However, the situation changed dramatically when Rochambeau learned on 14 Aug.
1781 that Admiral de Grasse and a large French fleet, along with a few additional French infantry, would soon arrive near the Chesapeake Bay. De Grasse was ready to support a military campaign in the region, but was not ready to go all the way to New York and warned that he had to return to the West Indies by mid-October. This news should set the stage for the last and decisive military campaign of the American Revolution. If war were to break out between France and Great Britain, the United States and England, Her Majesty and those United States, during the present war, will make it a common cause and will help each other with their good offices, their advice and their armed forces, according to the needs of the conjunctures who become good faithful allies. . . .