Complex sentence: The youngest son Gianfrancesco became Commissary General of the papal troops and was created Marquis of Rigattini (later exchange for Castel Romano) and Baldachin giving him the rank of Prince at the papal court.
Split into simpler sentences: The youngest son Gianfrancesco became Commissary General of the papal troops. He was created Marquis of Rigattini (later exchange for Castel Romano) and Baldachin giving him the rank of Prince at the papal court.