Presidio San Antonio de Béxar was a Spanish fort built near the San Antonio River, located in what is now San Antonio, Texas, USA. It was designed for protection of the mission system and civil settlement in central Texas. It also served to secure Spain's claim to the region from French, English and American aggression. It was built by Franciscan priest Antonio de Olivares and the Papaya; and along with the Misión de San Antonio de Valero (the Alamo) and the Acequia Madre de Valero, is the origin of the present city of San Antonio, Texas.