Complex sentence: He arrived in Mexico in 1761 and was sent to Baja California in 1768 and following the establishment of the mission at San Diego in 1769 he went to Northern California in 1773.
Split into simpler sentences: He arrived in Mexico in 1761 and was sent to Baja California in 1768. Following the establishment of the mission at San Diego in 1769, he went to Northern California in 1773.