<P> The Alamo Mission in San Antonio is commonly called The Alamo and was originally known as Misión San Antonio de Valero . It was founded in the 18th century as a Roman Catholic mission and fortress compound , and today is part of the San Antonio Missions World Heritage Site in San Antonio , Texas , United States . It was the site of the Battle of the Alamo in 1836 , and is now a museum in the Alamo Plaza Historic District . </P>
when was the mission san antonio de valero built
the 18th century