Complex sentence: The Massy/Masseys of the mid-west stem from Nicholas Massey (1630-1688), who migrated to Dorchester, Maryland, U.S.A. from the Isle of Ely.
Split into simpler sentences: The Massy/Massey's of the mid-west stem from Nicholas Massey (1630-1688). This Nicholas migrated to Dorchester, Maryland, U.S.A. from the Isle of Ely.