Mission San Rafael Arcángel was founded in 1817 as a medical '' asistencia '' ( '' sub-mission '' ) of the Mission San Francisco de Asís as a hospital to treat sick Native Americans of the Bay Area , making it Alta California 's first sanitarium .
Mission San Rafael Arcángel was founded in 1817 as a medical '' asistencia '' ( '' sub-mission '' ) of Mission San Francisco de Asís . 
 It was a hospital to treat sick Native Americans , making it Alta California 's first sanitarium .