Complex sentence: John Davison Rockefeller Sr. (July 8,1839--May 23,1937) was an oil industry business magnate and philanthropist, who is widely consideredthe wealthiest American of all time, and richest person in modern history.
Split into simpler sentences: John Davison Rockefeller Sr. (July 8,1839--May 23,1937) was an American oil industry business magnate and philanthropist. He is widely considered the wealthiest American of all time, and richest person in modern history.