French general Jean-Baptiste Donatien de Vimeur, comte de Rochambeau, commanded the French expeditionary army that fought beside Washington at Yorktown.
Rochambeau arrived in Newport, Rhode Island, in July 1780 with thousands of French troops sent to support the American Revolution. For much of the next year, the French and American armies coordinated their strategy while watching British forces in New York.
In 1781, Rochambeau and Washington marched south toward Virginia instead of attacking New York. Their forces joined the army commanded by the Marquis de Lafayette near Yorktown, where British general Charles Cornwallis was trapped. French troops formed a major part of the allied army and helped conduct the siege.
The victory depended on cooperation at sea as well as on land. Admiral François de Grasse defeated the British fleet at the Battle of the Chesapeake, preventing Cornwallis from receiving reinforcements or escaping by sea. Cornwallis surrendered on October 19, 1781.