Vacheron Constantin is a highly regarded watch manufacturer. Over the years, notable Vacheron Constantin patrons and timepieces owners include Queen Elizabeth II, Alexander I of Yugoslavia, Pope Pius XI, Napoléon Bonaparte, Marlon Brando, William James, John D. Rockefeller, Diana Princess of Wales, Harry S. Truman, and the Wright brothers. The Vacheron Constantin pocket watch No. 402833 (1929), which was owned by King Fuad I of Egypt, ranks as one of the most expensive watches ever sold at auction, fetching US$2.77 million (3,306,250 CHF) in Geneva on April 3, 2005. In 2015, Vacheron Constantin introduced the pocket watch Reference 57260, which currently holds the title of the most complicated mechanical watch ever made, with 57 horological complications.

(Source: WIkipedia)