The Convention of 1800, also known as the Treaty of Mortefontaine, was signed on September 30, 1800, by the United States and France. The difference in name was due to Congressional sensitivity at entering into treaties, due to disputes over the 1778 treaties of Alliance and Commerce between France and the U.S.

The Treaty of Alliance, also known as the Franco-American Treaty, was a defensive alliance between the Kingdom of France and the United States formed amid the American Revolutionary War with Great Britain. It was signed by delegates of King Louis XVI and the Second Continental Congress in Paris on February 6, 1778, along with the Treaty of Amity and Commerce and a secret clause providing for the entry of other European allies; together these instruments are sometimes known as the Franco-American Alliance or the Treaties of Alliance. The agreements marked the official entry of the United States on the world stage, and formalized French recognition and support of U.S. independence that was to be decisive in America's victory.