In 1718, Pierre Dugué de Boisbriand built the first Fort de Chartres. In 1722, St. Thérèse Langlois, a nephew of Boisbriand, founded Prairie du Rocher. The town was built on a tract of land donated by the Royal Indian Company. Boisbriand later became the commandant of the area. The town was strategically located along fertile Mississippi River bottomland. Surpluses from the productive cultivation by "habitants" later helped supply critical wheat and corn to New Orleans and other lower Louisiana Territory communities.