Complex sentence: He was the nephew of playwright John Millington Synge and the brother of the distinguished physicist John Lighton Synge who edited the collected works of Sir William Rowan Hamilton at Hutchie's urging.
Split into simpler sentences: He was the nephew of playwright John Millington Synge and the brother of the distinguished physicist John Lighton Synge. John edited the collected works of Sir William Rowan Hamilton at Hutchie's urging.