Over six months dragged on without a single Indian convert to mission San Diego. On January 24, 1770, the 74 exhausted men of the Portolá expedition returned from their exploratory journey up the coast to San Francisco. They had survived by slaughtering and eating their mules along the return trek south. Commander Gaspar de Portolá, engineer and cartographer Miguel Costansó, and friar Juan Crespí all arrived in San Diego with detailed diaries of their trip. They reported large populations of Indians living along the coast who seemed friendly and docile, ready to embrace the gospel. Serra fervently wrote to the guardian of the college of San Fernando, requesting more missionaries willing to face hardships in Alta California.