San Diego remained untouched by outsiders until 1769, when Gaspar de Portola, the first governor of California and commander of an effort to colonize the province, arrived with his "Sacred Expedition." Two days later came Junipero Serra, the new Father President of the Franciscan missions.
Serra founded San Diego on July 16, 1769 on a hill with a commanding view of the Indian settlements in Mission Valley and the bay. After a mass, Father Serra dedicated the first mission in California to the glory of God and in the same ceremony dedicated the first presidio -- or military settlement -- whose walls were to surround and protect the mission. Both were named San Diego. Earthworks for defense and huts for shelter were soon thrown up to create the first foothold of civilization in California on Presidio Hill.
While Presidio Hill might have been the "Plymouth Rock of the Pacific Coast," as some said, it certainly was no Rock of Gibraltar. Never garrisoned with more than a handful of soldiers, San Diego's earliest military establishment had a hard time defending the colony against Indians and outsiders; the soldiers soon earned a terrible reputation for abusing the Indians who joined the mission as neophytes (converts). That problem became more complicated in 1774 when Serra moved the mission from Presidio Hill to its present location five miles or so the east.
In response to abuse at the hands of the colonizers, a force of between 600 and 1,000 Indians attacked the lightly defended mission in November 1775, killing the Spanish blacksmith and carpenter and one of the two priests. All four soldiers then at the mission were wounded by arrows. When help finally arrived from the presidio, the attackers had left the area.