The missions of Alta California were founded for the purpose of Christianizing the American Indian population in those vicinities. In 1769, the Sacred Expedition was dispatched from Baja California to settle Alta California. Fathers Serra and Crespi, the spiritual leads, with two land parties and two seaborne parties totaling more than 100 men, under the command of Portola and Rivera y Moncada, assembled at San Diego. The first of the Franciscan missions — San Diego de Acala — was founded by Father Serra at a temporary location on July 16, 1769.

After making an exploratory trip north and spending seven months at San Diego until a relief supply ship arrived, Portola sent Serra and others by sea to Monterey where a second mission — San Carlos Borromeo — was established in June 1770. A year later, this mission was moved to a site on the Carmel River; it remained Serra's headquarters. Between 1771 and 1823, another nineteen missions were founded.

The mission system endured for sixty-five years. But in 1833, the Mexican government, which still controlled Alta California, decided to secularize the missions. The mission system ended the following year, and the mission buildings quickly fell into disrepair.

During the late nineteenth-century, two important records of the missions were created — Henry Chapman Ford's etchings (1883) and William Henry Jackson's series of albumen photographs (1885-1890). Sets of the original etchings and photographs are extremely rare. UC San Diego is fortunate to be able to display a selection of Jackson's original photographs, originally in the collection of Kenneth E. and Dorothy V. Hill, who generously loaned these items to UC San Diego for permanent exhibition on the web.