Rolex did not begin in a Swiss workshop. It began in London in 1905, when German-born Hans Wilsdorf and his British brother-in-law Alfred Davis started importing Swiss movements, fitting them into third-party cases, and selling them to jewelers who stamped their own names on the dial. Wilsdorf invented the word Rolex in 1908 because it was short, pronounceable in any European language, and sounded to him like a watch being wound. After the First World War, British taxes on luxury imports and duties on silver and gold pushed him to move the company to Geneva.

From there he built a brand through packaging and nerve: the screw-down Oyster case, a month of front-page Daily Mail ads after Mercedes Gleitze’s 1927 Channel swim, and the 1931 perpetual rotor. Then came the war. A 1941 Geneva police inquiry described him as a fervent admirer of the Hitler regime while finding no propaganda or suspicious activity, and MI5 investigated him as a suspected spy. This episode sets those files beside the watches he sent on credit to Allied prisoners of war.

• Gleitze spent more than 10 hours in the freezing Channel with an Oyster on a ribbon around her neck, and the watch came out dry and on time.
• Rolex supplied diving watches to Italian underwater demolition teams, and by 1944 a thousand watches went to German combat swimmers.
• More than 3,000 British officers at the Oflag VII-B camp in Bavaria ordered Rolex watches with no payment due until the war ended.
• Corporal Clive James Nutting ordered an Oyster 3525 chronograph at Stalag Luft III and used it to time guard patrols before the Great Escape of March 1944.
• After his wife died in 1944, Wilsdorf placed his shares in the Hans Wilsdorf Foundation, the private trust that still owns Rolex and discloses nothing.