The Battle of St. Louis, Spanish San Luis, also known as the Battle of Fort San Carlos, was an unsuccessful British-led attack on St. Louis (a French settlement in Spanish Louisiana, founded on the west bank of the Mississippi, after the Treaty of Paris (1763)) on May 26, 1780, during the Anglo-Spanish War. A force, composed primarily of Indians and led by a former British militia commander, attacked the settlement. The settlement's defenders, mostly local militia, under the command of Lieutenant Governor of Spanish Louisiana Fernando de Leyba, had fortified the town as best they could and successfully withstood the attack.