San Buenaventura Mission’s quadrangles were remembered through the childhood memories of Fernando Librado "Kitsepowit," a native Chumash speaker born there in 1839 who left the mission in 1855, after anthropologist John Harrington interviewed him in 1912 and 1913 about how the rooms had been used. The mission quadrangles began to deteriorate after the Mexican government secularized the mission in the 1830s and 1840s, sold the properties to private owners, and removed the Chumash from mission control. The absence of the Chumash led to further deterioration of the property. During the pastorate of Father Cypriano Rubio from 1878 to 1895, the last mission quadrangle rooms and walls were demolished, leaving only the church from what had once been a thriving mission system.