Complex sentence: Kean is a descendant of an old American family, and a direct descendant of Thomas Dudley (1576--1653), governor of the Massachusetts Bay Colony who has signed the Harvard College's charter.
Split into simpler sentences: Kean is a descendant of an old American family. He is also a direct descendant of Thomas Dudley (1576--1653), governor of the Massachusetts Bay Colony who has signed the Harvard College's charter.