Complex sentence: Lamy wrote to Bishop Zubiría asking him to explain the change of responsibility to the New Mexico priests, and when his request was unanswered went in person to Durango to meet with Bishop Zubiría, showing him the papal document appointed Lamy.
Split into simpler sentences: Lamy wrote to Zubiría asking him to explain the change of responsibility to the New Mexican priests. When his request was unanswered, he went in person to Durango to meet with Zubiría, showing him the papal document appointed Lamy.