Kelly headed the U.S. delegation at the Cannes Film Festival in April 1955. While there, she was invited to participate in a photo session with Prince Rainier III, the sovereign of the Principality of Monaco, at the Prince’s Palace, about 55 kilometers away from Cannes. After a series of delays and complications, she met him at the Prince’s Palace of Monaco on May 6, 1955. At the time of her initial meeting with him, she was dating the French actor Jean-Pierre Aumont. After a year-long courtship described as containing “a good deal of rational appraisal on both sides”, Prince Rainier married Kelly in 1956. The Napoleonic Code of Monaco and the laws of the Roman Catholic Church necessitated two ceremonies – both a civil ceremony and a religious wedding. The wedding was estimated to have been watched by over 30 million viewers on live television and was described by biographer Robert Lacey as “the first modern event to generate media overkill”. The 700 guests included several famous people, including Aristotle Onassis, Cary Grant, David Niven and his wife Hjördis, Gloria Swanson, Ava Gardner, Aga Khan III, Gloria Guinness, and many others. Frank Sinatra was invited but did not attend. Kelly and Rainier left that night for their seven-week Mediterranean honeymoon cruise on his yacht, Deo Juvante II.