There are only a few watches in the world indicating the time in accordance with the rules of the full 400-year cycle of the Gregorian calendar.
The first well-known is the pocket watch Patek Philippe Secular "true" Perpetual Calendar and Year Indication produced for the American collector Seth Atwood in 1972.
Sold at Christie's auction in 2007 for more than $1 million.
1986 – Patek Philippe, kaliber 89
The second is also the project of Patek Philippe, the famous caliber 89 produced in 1986.
1996 - Andersen Geneve
The third known design of the secular calendar is the module for the ETA 2892 movement manufactured by Sven Andersen under the Andersen Geneve brand in 1996. It will indicate the correct date in 2100, also includes every 400 years a leap year.
Notifier: Tomasz Jakubas
Other records: Timeline of Watchmaking Innovations