Zenith is a manufacture founded in 1865 by Georges Favre-Jacot in Le Locle, Switzerland. From the very beginning Zenith regularly took part in chronometry competitions organised by the Neuchâtel observatory, winning first place in 1903. Zenith is a brand very well known for its quality movements as well as its chronographs. The El Primero movement was launched in 1969 and is one of the first automatic chronographs. With the quartz crisis the manufacture decides to stop the production of mechanical watches in 1975. Despite the order to destroy all the production equipment for mechanical movements, the watchmaker Charles Vermot decides to keep and hide all the elements allowing the production of the El Primero calibre and so in 1984 Rolex turns to Zenith to equip its Rolex Daytona model with the automatic El Primero movement. Since then Zenith has reissued its El Primero calibre in numerous versions: A386, A385, 50th Anniversary,… it is an emblematic model much sought-after by collectors today.