Complex sentence: Peyramale, under instructions from his bishop, Monsignor Laurence, never visited the Grotto during any of the apparitions, and therefore never saw first-hand the effects which they produced in Bernadette and the onlookers.
Split into simpler sentences: Peyramale, under instructions from his bishop, Monsignor Laurence, never visited the Grotto during any of the apparitions. He therefore never saw first-hand the effects which they produced in Bernadette and the onlookers.