Is San Diego Calif named for Saint Didacus or Saint James?

San Diego, California, is named for Saint Didacus, who is also known as San Diego de Alcalá. The city was named by Spanish explorer Sebastián Vizcaíno in 1602, in honor of the saint. Saint James, or Santiago, is not associated with the city's name. Instead, the name reflects the influence of Spanish Catholicism in the region's history.