In the spring of 1776, Vergennes, the Foreign Secretary, saw an opportunity to humiliate France's long-standing enemy, Great Britain, and to recover territory lost during the Seven Years' War, by supporting the American Revolution. In the same year Louis was persuaded by Pierre Beaumarchais to send supplies, ammunition, and guns to the rebels secretly. Early in 1778 he signed a formal Treaty of Alliance, and later that year France went to war with Britain. In deciding in favor of war, despite France's large financial problems, the King was materially influenced by alarmist reports after the Battle of Saratoga, which suggested that Britain was preparing to make huge concessions to the thirteen colonies and then, allied with them, to strike at French and Spanish possessions in the West Indies. Spain and the Netherlands soon joined the French in an anti-British coalition. After 1778, Great Britain switched its focus to the West Indies, as defending the sugar islands was considered more important than trying to recover the thirteen colonies. France and Spain planned to invade the British Isles themselves with the Armada of 1779, but the operation never went ahead.