Complex sentence: Stavros George Livanos (1891--1963), a native of Chios, was the founder of the Livanos shipping empire and was a rival as well as father-in-law to both Aristotle Onassis and Stavros Niarchos.
Split into simpler sentences: Stavros George Livanos (1891--1963) was a native of Chios. He was the founder of the Livanos shipping empire and was a rival as well as father-in-law to both Aristotle Onassis and Stavros Niarchos.