The earliest Europeans to reach the site of San Francisco were a Spanish exploratory party in 1769, led overland from Mexico by Don Gaspar de Portolá and Fra. Joan Crespí. The Spanish recognized the location, with its large natural harbor, to be of great strategic significance. A subsequent expedition, led by Juan Bautista de Anza, selected sites for military and religious settlements in 1774. The Presidio of San Francisco was established for the military, while Mission San Francisco de Asís began the cultural and religious conversion of some 10,000 Ohlone who lived in the area. The mission became known as Mission Dolores, because of its nearness to a creek named after Our Lady of Sorrows.