The chain of missions established along the San Antonio River in the 18th century are reminders of one of Spain?s most successful attempts to extend its New World dominion from Mexico. Representing both church and state, these missions were charged with converting the local Native Americans, collectively called Coahuiltecans, into devout Catholics and productive members of Spanish society. More than just churches on the Spanish Colonial frontier, the missions also served as vocational and educational centers, economic enterprises involved in agricultural and ranching endeavors and regional trade. They were the greatest concentration of Catholic missions in North America and formed the foundation for what is today the thriving city of San Antonio. The park contains the historically and architecturally significant structures of missions Concepción, San José, San Juan and Espada. Other important cultural resources included are the historic Espada Dam and Aqueduct, acequia (irrigation) systems and the Rancho de las Cabras