Aristotle Socrates Onassis (/oʊˈnæsɪs/, US also /-ˈnɑː-/;[1] Greek: Αριστοτέλης Ωνάσης, romanized: Aristotélis Onásis, pronounced [aristoˈtelis oˈnasis]; 20 January 1906 – 15 March 1975)[2] was a Greek and Argentine[3][4] business magnate. He amassed the world's largest privately-owned shipping fleet and was one of the world's richest and most famous men.[5] He was married to Athina Mary Livanos, had a long-standing affair with opera singer Maria Callas and was married to American former First Lady Jacqueline Kennedy.[6]

Onassis was born in Smyrna in the Ottoman Empire and fled the city with his family to Greece in 1922 in the wake of the burning of Smyrna. He moved to Argentina in 1923 and established himself as a tobacco trader and later a shipping owner during the Second World War. Moving to Monaco, Onassis fought Prince Rainier III for economic control of the country through his ownership of SBM and its Monte Carlo Casino. In the mid-1950s, he sought to secure an oil shipping arrangement with Saudi Arabia and engaged in whaling expeditions. In the 1960s, Onassis attempted to establish a large investment contract—Project Omega—with the Greek military junta, and he sold Olympic Airways, which he had founded in 1957. He was greatly affected by the death of his son, Alexander in 1973 and died two years later.

Source: https://en.wikipedia.org/wiki/Aristotle_Onassis