Hans Wilsdorf and brother-in-law Alfred Davis started the "Wilsdorf and Davis" company in London, England, in 1905. Their initial primary focus was importing Swiss watch movement from Hermann Aegler and installing then in watch cases made by Dennison, and other companies. Various jewelers purchased these time pieces, printing their own names on the watches. However, some of the earlier watches had "W&D" printed inside the watch's case back.
Wilsdorf had the name "Rolex" registered as a trademark in 1908, and opened an office in La Chaux-de-Fonds, Switzerland. The word "Rolex" was chosen by Wilsdorf, though his reasons for making up this name are unclear. A common belief is that he wanted a name for his watches that could be easily pronounced in any language.
Kew Observatory, an astronomical and terrestrial magnetic observatory founded by King George III, awarded Rolex watches a Class A precision certificate in 1914, something usually only given to marine chronometers, used for celestial navigation. Wilsdorf moved the company to Geneva, Switzerland in 1919 and established it under the name of Rolex Watch Company. He did this because both export duties and taxes on gold and silver were driving manufacturing costs too high, and eating into the profits. The name of the company was changed later to Montres Rolex, SA and finally Rolex, SA.
A Rolex self-winding wrist watch was put on sale to the general public in 1931, which had a self-winding mechanism that was powered by the user's movement. Rolex helped develop quartz watches during the late 1960's and early 1970's, which eventually led to the creation of the Rolex Oysterquartz watch. Rolex created the first water-resistant watch, which the prototype was found to keep working at a depth of 11,000 feet. Rolex also produced wrist watches specifically designed for aviation, mountain climbing and deep-sea diving, and the Rolex GMT Master was manufactured at the request of Pan Am Airways to help pilots navigate through multiple times zones while traveling on long flights.