In Case you glance again around the history of Rolex, you’d detect that their reference numbers became lengthier with time. " For example, should you opened a Rolex catalog in the mid-'60s, you can've uncovered the following references stated next to each other: In 1985, Ulysse Nardin unveiled the Astrolabium https://www.watchesworld.com/a-history-of-watch-reference-numbers/