Spanish California refers to the period when California was part of the Spanish Empire, from the late 18th century until 1821. During this time, Spanish explorers and missionaries, such as Junípero Serra, established missions along the coast, aiming to convert Native Americans to Christianity and promote agriculture. The most famous of these missions is Mission San Diego de Alcalá, the first mission founded in 1769. In addition to missions, Spanish California saw the establishment of presidios, or military forts, to protect settlements. The region's economy was primarily based on agriculture and ranching, with cattle ranches becoming prominent. This era laid the foundation for California's cultural and historical identity.