 A series of four "presidios", or "royal forts", each manned by 10 to 100 men, were built by Spain in Alta California.California installations were established in San Diego (El Presidio Real de San Diego) founded in 1769, in San Francisco (El Presidio Real de San Francisco) founded in 1776, and in Santa Barbara (El Presidio Real de Santa Bárbara) founded in 1782.After the Spanish colonial era the Presidio of Sonoma in Sonoma, California was founded in 1834.)