Firstlaunched in 1978, theQuantime Perpetuelby Audemars Piguet was the worlds thinnest automatic perpetual calendar.This example captures much of the appeal of the earliest pieces, with its classic "Audemars Piguet" signature,crisp white dial and traditional yellow gold case.

The Quantime Perptuel

In the late 70s, complicated wristwatches were exceedingly rare. The Quartz Crisis had decimated the watchmaking industry, with the number of watchmakers in Switzerland having dropped from 1,600 to 600.Against all odds, three watchmakers at Audemars Piguet decided to develop the worlds thinnest automatic perpetual calendar movement. The project was , with the manufactures upper management completely unaware of what was going on. The watchmakers worked in their free time, often meeting at night to discuss their work.

In 1977, they surprised George Golay, the CEO of Audemars Piguet at the time, with the finished calibre. A risk taker whod already released the Royal Oak a few years prior, Golay was confident that the manufacture could successfully commercialise the automatic perpetual calendar. When it was launched in 1978, the Quantime Perpetuelwas the worlds thinnest automatic perpetual calendar. To put things in perspective, in 1984, only 1,066 perpetual calendars were produced in Switzerland. Of those, Audemars Piguet made 675.

Though the Royal Oak often gets credit for helping Audemars Piguet survive in the wake of the Quartz Crisis, evidence suggests the Quantime Perpetuel played a much greater role. According to the manufacture, 7,219 perpetual calendars were made over a fifteen year period, including some which were integrated into . A canvas to experiment with , 70 different models were produced, with around 200 variations documented.

A ClassicDesign

The lines of the Quantime Perpetuel were pennedby Jacqueline Dimier, whois considered by some as the protg of the legendary. The perpetual calendar indications are laid out in an intuitive manner. The date and day are shown at three and nine oclock respectively, with the months displayed at twelve oclock. A moonphase indication is placed at six oclock, with graduations for the moon position just above. The Audemars Piguet font is flat and restrained, imbuing this piece with a certain vintage appeal. Later versions of the same reference are known to have the more contemporary font, giving them a distinctively more modern appearance.

All of the subdials are recessed, which gives a satisfying level of depth to the overall design and creates some interesting effects when it interacts with the light.This is another subtle feature which is lost in subsequent iterations.Evidence suggests that the dial was manufactured byStern Crations, the storiedmanufacturer which also produced dials for theand the, among others.The gold stick hands provide excellent legibility against the white background.

At 36mm in diameter and less than 8mm thick, this 25657BA sits comfortably on the wrist. On the reverse of theyellow gold case, the watch features circular graining, along with finely-engraved markings, confirming the watches individual case number.

The Movement

This Quantime Perpetuel Automatique is powered by the Caliber 2120/2, derived from Jaeger-LeCoultres legendary . 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, a 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 Geneva stripes and edged with 21-carat gold, to increase the oscillating mass. The movement 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 Set

This Quantime Perpetuel 25657BA is accompanied by a QuantimePerpetuel leather folder, containing the watch instructions (stamped "August 1998") and a "Phases Of The Moon" card, for 1998. The watch also comes with a green leather pouch, setting pin,in addition tothe servicing paperwork and box from 2018. The watch is fitted to abespoke anthracite saffiano strap and isalso accompanied by its originalyellow gold tang buckle.

Viewings are suspended for the time being.

Closer look

Closer look