An annual calendar in the dynamic context of watchmaking is a feature of a mechanical watch.
Manual correction will often be required for the first of March, however, following the 28 days of February, or 29 in leap years.
Early Romans observed an 8-day market week, called the nundinal cycle, until the seven-day week was adopted during the reign of Emperor Constantine the Great (306-337).
[citation needed] In the world of watchmaking, the first annual calendar indicator introduced for a wristwatch was patented in 1996 by Patek Philippe.
5035, 5135, 5146, 5147, 5396 and 5960), Rolex (Sky Dweller), and Zenith (Captain Winsor).