 This expedition gave Spain some claim to the Northwest Territory, which was thwarted diplomatically by Great Britain and the young United States in their separate peace in the Treaty of Paris (1783).The Spanish also assisted in the Siege of Yorktown in 1781, the critical and final major battle of the North America theater.French General Jean-Baptiste Donatien de Vimeur, comte de Rochambeau, commanding his country's forces in North America, sent a desperate appeal to François Joseph Paul de Grasse, the French admiral designated to assist the Colonists, asking him to raise money in the Caribbean to fund the campaign at Yorktown.