In 1769 Don Gaspar de Portola’s expedition discovered this area and claimed it for King Carlos III of Spain. In August 1775, Lt. Juan Manuel de Ayala brought his sailing ship, the “San Carlos”, into San Francisco Bay and anchored in what is now Ayala Cove. His mission was to develop a map of the bay on which future Spanish ship captains could rely. Ayala has the distinction of being the first navigator to enter the San Carlos port.
After several explorations which included Fr. Junipero Serra and Don Jose Dario Arguello (Captain in the Castillian Army) Mission Dolores and the Presidio in San Francisco Were established. It is with Capt. Arguello that San Carlos history begins to take form.