Complex sentence: Pérez de la Serna continued as archbishop of Mexico until the arrival of the next viceroy, Rodrigo Pacheco y Osorio, marqués de Cerralvo in November, 1624, when he was assigned to the Spanish diocese of Zamora.
Split into simpler sentences: Pérez de la Serna continued as archbishop of Mexico until the arrival of the next viceroy, Rodrigo Pacheco y Osorio, marqués de Cerralvo in November, 1624. Then he was assigned to the Spanish diocese of Zamora.