Mission Basilica San Diego de Alcalá was the second Franciscan founded mission in the Californias, a province of New Spain. Located in present-day San Diego, California, it was founded on July 16, 1769, by Spanish friar Junípero Serra, in an area long inhabited by the Kumeyaay people. The current church, built in the early 19th century, is the fifth to stand …Mission Basilica San Diego de Alcalá was the second Franciscan founded mission in the Californias, a province of New Spain. Located in present-day San Diego, California, it was founded on July 16, 1769, by Spanish friar Junípero Serra, in an area long inhabited by the Kumeyaay people. The current church, built in the early 19th century, is the fifth to stand on this location. The mission site is a National Historic Landmark.