The mission period began in California in 1769 with the founding of the mission in San Diego. The mission period lasted until the mid-1830s. During this time twenty-one missions were created from San Diego to north of San Francisco, over a distance of 650 miles.

The missions had two primary objectives: one was religious, the other political and territorial. As the high-ranking Spanish official, Visitor-General Don José de Gálvez, explained on the eve of founding California 's first missions in 1768, "The object is to establish the Catholic Faith, to extend the Spanish domain, to check the ambitious schemes of a foreign nation."

These two objectives grew from a sequence of events dating to Christopher Columbus 's New World voyage of 1492. At that time the pope granted Spain rights to all of North and South America, except Brazil (which had already...