The Perpetual Calendar constitutes the high nobility of watchmaking. It was invented in 1770 by the French watchmaker Jean-Antoine Lépine.
Patek Philippe adapted to the wrist the principle of an “astronomical repeater watch with equation of time and perpetual calendar’ In 2023, the brand's Classic collection reinterprets the concept. Its movement has a mechanical “memory” of four years, or 1,461 days, with its gear reduction system from the wheel.