In 1957, while still married to husband Giovanni Battista Meneghini, Callas was introduced to Greek shipping magnate Aristotle Onassis at a party given in her honor by Elsa Maxwell after a performance in Donizetti's "Anna Bolena". The affair that followed received much publicity in the popular press, and in November 1959, Callas left her husband. Michael Scott asserts that Onassis was not why Callas largely abandoned her career, but that he offered her a way out of a career that was made increasingly difficult by scandals and by vocal resources that were diminishing at an alarming rate. Franco Zeffirelli, on the other hand, recalls asking Callas in 1963 why she had not practiced her singing, and Callas responding that "I have been trying to fulfill my life as a woman." According to one of her biographers, Nicholas Gage, Callas and Onassis had a child, a boy, who died hours after he was born on March 30, 1960. In his book about his wife, Meneghini states categorically that Maria Callas was unable to bear children. Various sources also dismiss Gage's claim, as they note that the birth certificates Gage used to prove this "secret child" were issued in 1998, twenty-one years after Callas's death. Still other sources claim that Callas had at least one abortion while involved with Onassis. In 1966, Callas renounced her U.S. citizenship at the American Embassy in Paris, to facilitate the end of her marriage to Meneghini. This was because after her renunciation, she was only a Greek citizen, and under Greek law of that time, a Greek could legally marry only in a Greek Orthodox church. As she had married in a Roman Catholic church, this divorced her in every country except Italy. The renunciation also helped her finances, as she no longer had to pay U.S. taxes on her income. The relationship ended two years later in 1968, when Onassis left Callas in favor of Jacqueline Kennedy. However, the Onassis family's private secretary, Kiki, writes in her memoir that even while Aristotle was with Jackie, he frequently met with Maria in Paris, where they resumed what had now become a clandestine affair.