Father Junípero Serra founds California's first mission, Mission San Diego de Alcalá. Over the following decades, it evolves into the city of San Diego, California.

Mission Basilica San Diego de Alcal (Spanish: Misin San Diego de Alcal) was the second Franciscan founded mission in The Californias (after San Fernando de Velicata), a province of New Spain. Located in present-day San Diego, California, it was founded on July 16, 1769, by Spanish friar Junpero Serra in an area long inhabited by the Kumeyaay people. The mission and the surrounding area were named for the Catholic saint Didacus of Alcal, a Spaniard more commonly known as San Diego. The mission was the site of the first Christian burial in Alta California. The original mission burned in 1775 during an uprising by local natives. San Diego is also generally regarded as the site of the region's first public execution, in 1778. Father Luis Jayme, California's first Christian martyr who was among those killed during the 1775 uprising against the mission, lies entombed beneath the chancel floor. 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.

Junípero Serra y Ferrer (; Spanish: [xuˈnipeɾo ˈsera]; Catalan: Juníper Serra i Ferrer; November 24, 1713 – August 28, 1784) was a Spanish Roman Catholic priest and missionary of the Franciscan Order. He is credited with establishing the Franciscan Missions in the Sierra Gorda, a UNESCO World Heritage Site. He later founded a mission in Baja California and the first nine of 21 Spanish missions in California from San Diego to San Francisco, in what was then Spanish-occupied Alta California in the Province of Las Californias, New Spain.

Serra was beatified by Pope John Paul II on 25 September 1988 in Vatican City. Amid denunciations from Native American tribes who accused Serra of presiding over a brutal colonial subjugation, Pope Francis canonized Serra on 23 September 2015 at the Basilica of the National Shrine of the Immaculate Conception in Washington, D.C., during his first visit to the United States. Serra's missionary efforts earned him the title of "Apostle of California".Both before and after his canonization, Serra's reputation and missionary work during the Spanish occupation have been condemned by critics, who cite alleged mandatory conversions to Catholicism, followed by abuse of the Native American converts.