Perpetual calendars are the authoritative complications of calendar watches. When Audemars Piguet created the Quantieme Perpetual Automatique in the late 70s, perpetual calendars were scarce. Upon its release in 1978, the Quantieme Perpetual represented one of the most significant horological innovations of the period - introducing the world’s thinnest, self-winding perpetual calendar movement. It achieved its ultra-slim profile (3.95 mm) by adapting the renowned calibre 2120 movement, launched in ’67.

In 1875, Jules Louis Audemars and Edward Auguste Piguet founded the Swiss watch manufacturing company Audemars Piguet in Le Brassus, Vallée de Joux. In 1955, the brand began production of its first series of perpetual calendar wristwatches to feature a leap year indication. A specialist in the manufacture of complications since it was established, Audemars Piguet continued to produce a variety of high-quality perpetual calendars throughout the late 70s to the early 2000s, considered some of the most impressive of the modern era.

This rare platinum example ref. PT25657 perfectly illustrates why the Quantieme Perpetual seems so under-appreciated. Understated both in styling and size - modest (by today's standards) at 36 mm - with a slim case matched by an ultra-thin, automatic perpetual calendar movement. The platinum case features a stepped bezel and short, down-tuned lugs, which work proportionately well together. On the reverse, the watch is features circular graining, along with finely-engraved markings.

The sub-dial at 3 o'clock shows the date, in a slightly recessed sub-register, giving depth to the otherwise smooth white dial. In a similar fashion, the days of the month are placed at 9 o'clock, with the months of the year at 12. The moon-phase is placed at six o'clock, with graduation for moon age above. The white dial is further accented with applied index markers - corresponding harmoniously with Audemars Piguet’s ‘stick’ hands. The index markers and hands are subtle in form, with excellent legibility against the white backdrop.

This Quantieme Perpetual Automatique is powered by the AP caliber 2120/2, derived from Jaeger-LeCoultre’s legendary ultra-thin JLC 920 calibre movement. The caliber 2120 was an initial project of Jaeger LeCoultre in 1967, funded and contributed by Audemars Piguet, and famous for its adoption by Audemars Piguet, Patek Philippe and Vacheron Constantin. The ultra-thin automatic 2120/2 calibre features 38 working jewels, Gyromax balance and four ruby wheels to support the full-diameter rotor, which runs on a beryllium rail for stability. The rotor is decorated with Genevan stripes and edged with 21-carat gold, to increase the oscillating mass. The AP calibre 2120 remains the thinnest full-rotor self-winding movement in the world, considered by many as one of the most technically refined wrist-watch movements ever made.

The watch comes as a full set, accompanied by its original Audemars Piguet box, Certificate of Origin and literature and setting pin. It also comes with a period-correct, Audemars Piguet winding box. The watch was recently fully-serviced in 2017 by Audemars Piguet. It's fitted to one of our Santorini, blue saffiano leather strap, as well as its original platinum tang buckle.

Viewings can be arranged in Central London by appointment.