Complex sentence: Abigail Greene "Abby" Aldrich (October 26,1874--April 5,1948) was an American socialite, philanthropist, wife of John D. Rockefeller, Jr., and prominent member of the Rockefeller family.
Split into simpler sentences: Abigail Greene "Abby" Aldrich (October 26,1874--April 5,1948) was an American socialite and philanthropist. Through her marriage to philanthropist John D. Rockefeller, Jr., she was a prominent member of the Rockefeller family.