Complex sentence: He was educated at Mantes and at the University of Paris, afterwards becoming chaplain to the French king Philip Augustus, who employed him on diplomatic errands, and entrusted him with the education of his natural son, Pierre Charlot.
Split into simpler sentences: He was educated at Mantes and at the University of Paris. Later, he became chaplain to the French king Philip Augustus, who employed him on diplomatic errands, and entrusted him with the education of his natural son, Pierre Charlot.