France became the United States’ first formal military ally during the American Revolution.
The United States and the Kingdom of France signed the Treaty of Alliance on February 6, 1778, in Paris. The agreement followed the American victory at Saratoga, which helped persuade French leaders that the rebellion had a realistic chance of success. A companion Treaty of Amity and Commerce recognized American independence and established commercial relations.
France provided weapons, money, ships, supplies, and troops. French naval power was especially important during the Yorktown campaign, when French warships helped prevent British relief forces from reaching the besieged army. French soldiers also fought alongside American forces.
The alliance had strategic roots in France’s rivalry with Great Britain, including the consequences of the Seven Years’ War. Spain later joined France against Britain in 1779, but it did not sign the same formal military alliance with the United States. The Franco-American alliance was eventually weakened by the French Revolution and formally ended in 1800.