Complex sentence: Thomas Jackson Walker III was born in Edgartown, Massachusetts (on the island of Martha's Vineyard), on 6 August 1919, the descendant of three great-grandfathers who were whaling ship captains.
Split into simpler sentences: Thomas Jackson Walker III was born in Edgartown (Island of Martha's Vineyard), Massachusetts, on 06 AUG 1919. He is the descendant of three great-grandfathers who were whaling ship Captains.