Complex sentence: He entered the Roman Curia five years later and then steadily climbed the career ladder in the administration and was ordained priest in 1710, served as a "chargé d'affaires" in the nunciature in Spain from 1712 to 1716.
Split into simpler sentences: He entered the Roman Curia five years later and then steadily climbed the career ladder in the administration. He was ordained as a priest in 1710, served as a "chargé d'affaires" in the nunciature in Spain from 1712 to 1716.