Like many of the products released by Rolex in the "Golden Age" sports watches of the 1950s, Submariner's early life was particularly turbulent. Reference for debut. 6204 was publicly unveiled at the Basel Fair in 1954 and was an immediate success. However, Rolex also introduced two other versions at almost the same time, namely ref. 6200 and reference 6205. There is controversy as to which model was actually the first. All models occurred in such a short period of time and a long time ago (and the reference numbers are obviously not continuous). However, a careful examination of the serial number can confirm that it is indeed the referee who entered the market first. 6204.