Complex sentence: His "Chronica Majora" is an oft-cited source, though modern historians recognize that Paris was not always extremely reliable since he tended to write to glorify Emperor Frederick II, and denigrate the Pope.
Split into simpler sentences: His "Chronica Majora" is an oft-cited source, though modern historians recognize that Paris was not always reliable. He tended to write to glorify Emperor Frederick II, and denigrate the Pope.