Complex sentence: He taught painting at the Academy of San Carlos, and in 1927 was appointed director of the Centro Popular de Pintura in Nonoalco, whose mission was to make art accessible to the working classes.
Split into simpler sentences: He taught painting at the Academy of San Carlos, and in 1927 was appointed director of the Centro Popular de Pintura in Nonoalco. Its mission was to make art accessible to the working classes.