Complex sentence: Henry Pierrepont, 1st Marquess of Dorchester, PC, FRS (March 1606--8 December 1680) was an English peer, the son of the Robert Pierrepont, 1st Earl of Kingston-upon-Hull.
Split into simpler sentences: Henry Pierrepont, 1st Marquess of Dorchester, PC, FRS (March 1606--8 December 1680) was an English peer. He was the son of Robert Pierrepont, 1st Earl of Kingston-upon-Hull.