As early as the 16th century, renowned astronomers and natural scientists were already studying the peculiarities and behaviour of the pendulum, or what was then called the gravity pendulum. In elaborate experiments and calculations, they came to the conclusion

Erwin Sattlers grandfather, Heinrich sattler, patented already on the 4th of March 1903 a desk or shelf clock with perpetual calendar. The model Opus Perpetual embodies the most modern interpretation of the perpetual calendar in Erwin Sattler’s collection …

“What you can’t buy, you simply have to do it yourself”, was Heinrich Sattlers motto. Erwin Sattlers grandfather was horologist and patented on the 4th of March 1903 a desk or shelf clock with perpetual calendar.