Los Adaes, in present-day western Louisiana near Robeline, was a Spanish presidio and mission that served from 1721 to 1773 as the capital of Tejas on New Spain’s northeastern frontier and the first capital of Texas. Established after French expansion and the seizure of an earlier mission, it stood near Natchitoches to shield reopened eastern Tejas missions. Though built for defense, daily life was marked more by isolation, shortages, and dependence on nearby French trade than by war, while missionary efforts among the Adai largely failed. After Spain acquired western Louisiana, the post lost its purpose, was abandoned, and its settlers were forced to move. Archaeology has since made it a major site for studying the Spanish colonial frontier and Adai Caddo culture.