Quantième

“De quantum” refers to “how much” and denotes a number, specifically the date of the month.

The simple calendar is an evolution of 17th-century astronomical watches, using a complex mechanism of gears, wheels, levers, and snails to display typically the date from 1 to 31 of the month. This indication can be achieved with hands, discs, or rollers. These movements require manual adjustment at the beginning of each month.

The first perpetual calendar watch was introduced in 1925. It automatically adjusts for varying month lengths, including leap years, without frequent manual adjustment. The movement is capable of anticipating these variations without external intervention. Some models also feature a moon phase indicator, with the first model introduced in 1984.

Watches equipped with a perpetual calendar are considered high complication timepieces, showcasing the technical expertise and precision required to design and manufacture a mechanism capable of autonomously managing the subtleties of the calendar.