Jean-Baptiste Donatien de Vimeur, comte de Rochambeau was a French Royal Army officer who played a critical role in the American victory at the siege of Yorktown in 1781 during the American Revolutionary War. He was commander-in-chief of the Expédition Particulière, the French expeditionary force sent to North America during the conflict. He worked closely and well with George Washington, commander-in-chief of the Continental Army.