Complex sentence: Robert Owen Lehman, Sr. (September 29,1891--August 9,1969) was an American banker, head of Lehman Brothers for decades and a notable race-horse owner, and important art-collector and philanthropist.
Split into simpler sentences: Robert Owen Lehman, Sr. (September 29,1891--August 9,1969) was an American banker. He was the head of Lehman Brothers for decades and a notable race-horse owner, and important art-collector and philanthropist.