The Swiss luxury watch and clockmaker Patek Philippe SA has its headquarters in Geneva Canton and Vallée de Joux, founded in 1839. In Switzerland it has been owned by the Stern family since 1932. Patek Philippe is one of the world's oldest watchmakers, with an unbroken history of watchmaking since its establishment. It designs and manufactures all of the timepieces and movements including some of the automatic watches that are most common. The business has over 400 retail stores worldwide, with over a dozen logistics centres in Asia, Africa, North America with Oceania. The Patek Philippe Museum in Geneva opened in 2001. Patek Philippe is widely regarded as one of the world's most prominent watch-makers. Over the years the prominent followers and advocates of Patek Philippe have included Queen Victoria, Queen Elizabeth II, Pope Pius Xii, Marie Curie, Albert Einstein, John F. Kennedy, Nelson Mandela, Pablo Picasso, Pyotr Tchaikovsky and Leo Tolstoy among others. Seven watches as of December 2019 are Patek Philippe in the top ten most expensive watches ever priced at auctions worldwide. Yes, Patek Philippe Grandmaster Chime Ref 6300A-010 now retains the distinction of the most expensive watch ever sold on sale, while Patek Philippe Henry Graves Supercomplication, the most complex automatic watch in the world prior to 1989, still holds the distinction of the most expensive pocket watch ever sold at auction. In 1958 Charles Stern's son Henri Stern was elected president of Patek Philippe. Alan Banbery, who had previously designed Universal's Compax movements and served as a horologist with London's Garrard & Co, would assume the role of Marketing Director in 1965 and finally write official reference books on Patek Philippe's vintage pocket watches and chronographs. Philippe Stern, Henry Stern's wife, was made the company's President in 1993. In 1996, he began publishing the twice-a-year Patek Philippe Magazine, which is reserved for the watch owners and has received contributions from many notable writers including Nobel Laureates Gao Xingjian and José Saramago. Then in the year 2009, his father's reins were taken up by Philippe Stern's son Thierry Stern. The business created 40,000 timepieces in 2010, and manufactured 58,000 pieces in 2017, says Thierry Stern. In 2018, the figure grew to 62,000 and Patek Philippe will then gradually increase the quantity of timepieces created each year along with a limit to maintain consistency and exclusiveness. The brand is also a registered member of Swiss Watch Industry Federation FH. One of the slogans for the company by Patek Philippe is "You never really buy a Patek Philippe. You only look after it for the next generation." The slogan was launched after the brand unveiled the "Generations" campaign in 1996. Patek Philippe manufactures own parts for the watch. Unlike other Swiss brands, the firm mostly produces mechanical moves but also quartz watches with automatic or manual winding system. However, Patek Philippe was one of the twenty Swiss watch companies who formed the Center Electronique Horloger and in partnership produced the first Swiss quartz movements, such as the Beta 21 mechanism, which other manufacturers used in their watches. The firm had already developed a prototype for a mechanical electronic wristwatch in the 1950s, reference 3414. Its apps such as everlasting time, split-second wrist, chronograph, and repeater minutes, Patek Philippe popularised optical watches. In 2009, the brand announced that it will imprint all of its new mechanical timepieces with the Patek Philippe Seal, which includes an precision of 2 seconds per day for diameters not greater than 20 mm and 4 seconds per day for diameters smaller than 20 mm, meeting the highest quality in the watch manufacturing industry and thereby eliminating the Geneva Seal.