Alexander Socrates Onassis was an American-born Greek businessman. He was the son of the Greek shipping magnate Aristotle Onassis and his first wife Tina Livanos. He and his sister Christina Onassis were upset by his father's marriage to Jacqueline Kennedy, and he was credited with attempting to improve the relationship between his father and Stavros Niarchos.

Aristotle Socrates Onassis was a Greek and Argentine business magnate. He amassed the world's largest privately-owned shipping fleet and was one of the world's richest and most famous men. 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.