The California missions were a series of 21 religious outposts established by Spanish colonists between 1769 and 1833. Their primary purpose was to spread Christianity among the indigenous peoples and to secure Spanish territorial claims in the region. Each mission was typically located near a water source and included a church, living quarters, and agricultural areas. The missions were part of a larger system that included Franciscan friars, who played a key role in their establishment and operation. Today, many of these missions, such as Mission San Diego de Alcalá and Mission Santa Barbara, are preserved as historical sites, showcasing California's early colonial history.