Rolex 1215

History: The Rolex 1215 is a manual winding movement by Rolex. 18,000 A/h, 17 jewels, central seconds, date, power reserve 58 hours. In the variant without date it is called Calibre Rolex 1210. The 1215 movement is usually stamped "1210".

Manual winding movement; Escapement: Stone lever; Yoke winding system; Breguet hairspring; Shock protection Kif-Flector; Escape wheel in Kif Duofix Combi chuck; Balance staff U2357; Stem W2815.

For some reason, I have yet to fathom, some watches with this movement are denoted as Calibre 854....

Manufacturer: Rolex SA (/ˈroʊlɛks/) is a Swiss luxury watchmaker. The company and its subsidiary Montres Tudor SA design, manufacture, distribute and service wristwatches sold under the Rolex and Tudor brands. Founded by Hans Wilsdorf and Alfred Davis in London, England in 1905 as Wilsdorf and Davis, Rolex moved its base of operations to Geneva, Switzerland in 1919. Forbes ranked Rolex 64th on its 2016 list of the world's most powerful global brands.[Rolex is the largest single high end watch brand. The company is owned by the Hans Wilsdorf Foundation, a private family trust.

Alfred Davis and his brother-in-law Hans Wilsdorf founded Wilsdorf and Davis, the company that would eventually become Rolex SA, in London, England in 1905. Wilsdorf and Davis' main commercial activity at the time involved importing Hermann Aegler's Swiss movements to England and placing them in high-quality watch cases made by Dennison and others. These early wristwatches were sold to jewellers, who then put their own names on the dial. The earliest watches from Wilsdorf and Davis were usually hallmarked "W&D" inside the caseback.

From Wikipedia