David Bennett is the Worldwide Chairman of Sotheby's International Jewellery Division and the Chairman of Sotheby's Switzerland. He has sold four out of the five most expensive jewels in auction history. Having worked as an auctioneer at the firm since 1978, Bennett is renowned internationally as an authority on jewellery. He played a key role in numerous illustrious sales, such as the 'Jewels of the Duchess of Windsor' (1987), a tiara from the Collection of Princess Katharina Henckel von Donnersmarck (2011) and Henry IV of France's Beau Sancy (2012). Daniela Mascetti is Sotheby's Chairman of Jewellery in Europe. She joined Sotheby's in 1980, opening the firm's Milan-based department. She is one of Sotheby's most experienced scholars in the history of jewellery, and has collaborated extensively in the sales of historic collections. Her research has assisted with several notable auctions, from The Jewels of the Duchess of Windsor to the collections of Elton John and Gina Lollobrigida.