2025 marks some big anniversaries in the watch industry with several brands and watches set to celebrate milestone birthdays. In anyone’s book 100 years is quite the landmark and thanks to the 1925 Patek Philippe perpetual calendar ref. 97975 this year will see the centenary of the first wristwatch perpetual calendar. Perhaps the most impressive fact is 100 years on and this complication is still at the top of the horological food chain.
The first thing to note about the Patek Philippe 97975 is that it wasn’t the first perpetual calendar watch. The earliest recorded perpetual calendar actually comes from English watchmaker Thomas Mudge. His earliest (known) calendar pocket watch is dated 1762. It was over 160 years later before the complication found its way onto the wrist.
Patek Philippe Calibre 97975
The second thing to note about the Patek 97975 is that it was never intended to be a wristwatch and as result contains a ‘hand-me-down’ movement. In fact, the 97975 started life as a ladies pendant watch and was converted to a wristwatch as an afterthought when a perpetual calendar pendant failed to catch on with customers. Patek’s perpetual calendar pendant dates back to 1898 however it wasn’t until 1925 that the movement was repurposed in a yellow gold 34mm case to create the 97975. The first perpetual calendar ever in a wristwatch.
By today’s standards a 34mm perpetual calendar is definitely on the small side, but as with most Patek’s of the era its design is a classic and intricate dress watch. The white dial is contrasted with predominantly black numerals and text. Only the outer red numbers, to indicate the date, provide any colour to the dial. The subdial configuration shows the day at 12 o’clock, moonphase at 3 o’clock, month at 6 o’clock and small seconds at 9. This layout for Patek Philippe perpetual calendars didn’t last long with subsequent watches, including the modern day 5327 Grand Complication, moving the date and moonphase to the more accepted 6 o’clock position.
Patek Philippe 5237R Perpetual Calendar, image credit: Watchcollecting
As is only befitting a watch of this calibre, the case was intricately designed to include hand engraved sides and lugs. The oversized crown is also hand engraved and fluted. This artistic aesthetic is a distant relative to some of the perpetual calendars you’ll find in today’s sportier watches, such as the Nautilus 5740/1G.
Patek Philippe’s first perpetual calendar wristwatch was a one off and not a production model. It was sold in 1927 to Thomas Emery, an American collector, and today finds itself safely housed in Patek’s Museum. Whilst it is highly unlikely to ever come to market if it did ever go under the hammer at auction the price is almost unfathomable. The Patek Philippe 97975 is about as collectable as it could possibly get.
Patek Philippe In-Line Perpetual Calendar ref. 5236P with just a single subdial
Patek Philippe and perpetual calendars go together like a tasting menu and wine pairing. If the 97975 was just the canapé, then what followed was a meal of historical firsts. In 1937 Patek created the first retrograde perpetual calendar, in 1941 the first perpetual calendar chronograph and first production perpetual calendar, and in 1962 the first self-winding perpetual calendar. This only covers a few of the achievements Patek has chalked up along its perpetual calendar journey.
Over the years Patek have refined and developed the complication, extensively redesigning it from the original pendant movement. At its core the function and use of the perpetual calendar remains unchanged providing accurate readings of the day, date, and month while also accounting for leap years. What has changed, however, is how this information is displayed and incorporated into the design of the dial. Where the Patek 97975 used every centimetre of dial real estate to accommodate 4 subdials today this can be done with much more clarity. The current Patek 5236 has only a small seconds subdial with the day, date and month displayed with apertures of text.
H. Moser and Cie Endeavour Perpetual Calendar Tantalum Blue Enamel
While Patek Philippe will always be closely aligned to this complication, it has become a staple across haute horological brands. If you really want to see how the design of perpetual calendars has progressed, you should take a look at the H. Moser & Cie Endeavour Perpetual Calendar At first glance you wouldn’t believe the watch contains more than the time and date.
Similarly, in 2024 the perpetual calendar saw arguably its biggest update in recent history. The IWC Portugieser Eternal Calendar became the first watch that can remain accurate (if regularly wound) for 45 million years! Until this point perpetual calendars have suffered from a minor problem. The year 2100 should be designated a leap year however due to the way the Gregorgian calendar works it won’t be.
IWC Portugieser Eternal Calendar, accurate for 45 million years
This means all perpetual calendars will need resetting in the year 2100, except for the IWC. Thanks to the ‘400-year-gear’, a gear that rotates every 400 years and skips leap years, such as the year 2100, the Portugieser Eternal Calendar should never need resetting. Where perpetual calendars go from here in the next 100 years only time will tell. Since Patek have been stewards of the complication for 100 years, no doubt they will continue to be at the forefront of its development.
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