<P> Mission San Gabriel was founded on September 8 , 1771 by Fray Angel Francisico de Sonera and Fray Pedro Benito Cambon . The planned site for the Mission was along the banks of the Río de los Temblores ( the River of the Earthquakes -- the Santa Ana River ) . The priests chose an alternate site on a fertile plain located directly alongside the Rio Hondo in the Whittier Narrows . The site of the Misión Vieja ( or `` Old Mission '' ) is located near the intersection of San Gabriel Boulevard and Lincoln Avenue . In 1776 , a flash flood destroyed much of the crops and ruined the Mission complex , which was subsequently relocated five miles closer to the mountains in present - day San Gabriel ( the native settlement of ' Iisanchanga ) . The Mission is the base from which the pueblo that became the city of Los Angeles was sent . On December 9 , 1812 ( the `` Feast Day of the Immaculate Conception of the Blessed Virgin '' ) , a series of massive earthquakes shook Southern California . The 1812 Wrightwood earthquake caused the three - bell campanario , located adjacent to the chapel 's east façade , to collapse . A larger , six - bell structure was subsequently constructed at the far end of the capilla . While no pictorial record exists to document what the original structure looked like , architectural historian Rexford Newcomb deduced the design and published a depiction in his 1916 work The Franciscan Mission Architecture of Alta ( upper ) California . </P>
who was the founding father of the san gabriel mission
Fray Angel Francisico de Sonera Fray Pedro Benito Cambon