- In the early 1990s, as Roth began developing a perpetual calendar for his signature double-ellipse case, with the help of his neighbor—none other than Philippe Dufour the two set out to create the Perpetual Calendar.

- The present example, in yellow gold, is an early and rare version of this landmark reference. It features day and month apertures and a “semi-instantaneous” calendar mechanism—an ambitious concept born from the duo’s original goal of achieving full instantaneity.

- In excellent condition and complete with its Certificate of Origin and presentation box, the present lot embodies Roth’s dedication to pushing boundaries while staying true to elegant design.