The concept of an ultra-thin, automatic perpetual calendar seems like an obvious one in classic watchmaking – pairing one of the most prestigious complications with a convenient winding system and a slim, discrete profile. However, it would take the complete disruption of the industry, with the advent of the Quartz Crisis, for it to appear. Once the first one was released, it spawned an entire category, which feels distinctly its own.

Arguably, quite a few models could fall under this category. However, for the purpose of this article, we’ll focus on those which we consider having the most far-reaching legacy, namely the ones created by the ‘Holy Trinity’ brands. Within the span of seven years, between 1978 and 1985, Audemars Piguet, Vacheron Constantin, and Patek Philippe all introduced their own ultra-thin, automatic perpetual calendars – the references 5548, 43031, and 3940. These were amongst the first perpetual calendars to be produced in a series, marking a fundamental departure from the past, when each of these manufactures would only have produced a few dozen of these pieces a year, at the very most. It demonstrated a renewed faith in the future of complicated horology in the wake of an existential crisis.

All three of these watches share key characteristics, not only in their physical form, but in how they were first conceived and how they are collected today. However, what is perhaps the most interesting is how they differ. For example, whilst Audemars Piguet experimented wildly with the design of the complication, Patek Philippe saw itself as the purveyor of classic, restrained aesthetics. From varying dial layouts to different approaches in movement construction, there are some key differences that give all of them their own distinct appeal. Leaning on our own experiences handling and researching these pieces, as well as information from the archive departments at Audemars Piguet and Vacheron Constantin, we thought we’d take a closer look at the battle between these ultra-thin, automatic perpetual calendars.

The perpetual calendar has long fascinated watchmakers. Since the very first one left the workbench of Thomas Mudge in 1762, it has been viewed as one of the great technical hurdles of horology. Indeed, the ability to construct this complication is a skill few have mastered. Famously, Abraham-Louis Breguet made a handful of them, although the cost of producing these was so high that only a select few of his clients could justify purchasing one. This was due to the complexity, time and skill involved in assembling the complication, even for such an accomplished watchmaker.

Within a perpetual calendar, certain parts don’t budge for hundreds of days, and then must accurately and precisely move into place when they’re needed. This level of precision is what makes the complication so challenging. Patek Philippe were the first to put it inside a wristwatch in 1925, and then again to serially produce it in 1941, with the reference 1526. This decade-and-a-half gap between the two models goes to show just how challenging the process must have been. Patek Philippe were also the first to create an automatically winding perpetual calendar movement, with the reference 3448.

A few years later, the advent of the Quartz Crisis threatened the very existence of mechanical timepieces, including perpetual calendars, which became increasingly irrelevant in the face of cheap, reliable, battery-powered movements. This seismic event decimated the watchmaking industry, with the number of watchmakers in Switzerland dropping from 1,600 to 600. As a result, very few truly complicated pieces were made over the next decade or so. Most manufactures had either embraced the idea that quartz movements represented the future or were too financially weakened to invest in creating costly pieces without the guarantee that anyone would want to purchase them.

However, a few mavericks saw things differently. Whereas many tried to move towards innovation and progress, a handful of individuals saw the value of doubling down on tradition, as one of the only ways to ensure that watchmaking could survive. Against all odds, the perpetual calendar experienced a revival. Within a span of seven years, between 1978 and 1985, Audemars Piguet, Vacheron Constantin, and Patek Philippe all introduced their own ultra-thin, automatic perpetual calendars – the references 5548, 43031, and 3940. Other manufacturers, such as Breguet or Blancpain, also embraced this direction, seeing value in fighting against the tide of change.

These pieces mark a clear transition in the history of horology. Under threat, a handful of manufacturers decided to focus on their heritage, producing classic, complicated pieces for a new generation of collectors. In recent times, these pieces have been rediscovered by the horological community, on account of their rich historical context, impressive mechanics, and balanced aesthetics.

Why do we categorise the three watches from the ‘Holy Trinity’ in a cohesive group? They are certainly not the only perpetual calendars to have been produced through the ‘80s and ‘90s. However, they do share a set of qualities, and this seems to unite them in collectors’ minds today.

All three brands – Audemars Piguet, Vacheron Constantin, and Patek Philippe – introduced these models to help them survive the most disruptive period in the history of modern watchmaking. While the origin story may differ from one manufacture to the other, they were all born from the need to survive. Because of this, they needed to be commercially successful and sustainable, so they were produced at a much larger scale than any other perpetual calendar in the past. For some context, between 1962 and 1981, it is understood that Patek Philippe produced around 600 examples of the reference 3448 – around 32 pieces a year. With the reference 3940, their annual production increased by several multiples, with some estimating that up to 400 pieces could’ve left the manufacture per year. In a way, these were the first truly modern perpetual calendars to be produced at scale.

All three manufactures also chose to make their movements automatic and ultra-thin. The former was motivated by a desire to make these pieces appealing to a wide audience, which would’ve favoured the practicality of an automatic calibre, rather than a manual-wound one. Despite housing a rotor, it is important to note that all three models are remarkably thin, which helps to keep the overall aesthetics restrained and balanced. To achieve this, Audemars Piguet and Vacheron Constantin picked the same ultra-thin ébauche, the Jaeger-LeCoultre 920, whilst Patek Philippe opted for a micro-rotor calibre instead.

Because of the period in which they were produced, all these pieces combine both vintage and modern characteristics, from production techniques to aesthetics. They all adopt a relatively restrained case size, traditional dial layout and were originally introduced in yellow gold with a closed dial. At the same time, these models also integrate some more contemporary characteristics. Notably, both Audemars Piguet and Vacheron Constantin experimented with various case designs, dial colours, and skeletonised movements, whilst Patek Philippe also introduced sapphire casebacks for most of its later pieces.

Overall, the similarities between these pieces are rather evident. As the three manufactures which most embody classic Swiss watchmaking, it makes sense that Audemars Piguet, Vacheron Constantin and Patek Philippe would take a comparable approach. With this shared context in mind, we thought we’d look more closely at each of the three models, in chronological order, comparing them as we go along.

Perpetual calendars were nothing new to Audemars Piguet. They had been making them in wristwatch form as far back as 1948, with the reference 5516. Only 12 examples were ever made, most of which feature a design which would later influence the creation of reference 5554, which we’ll be focusing on here. Arguably, this was the first perpetual calendar of the modern era.

As François-Henry Bennahmias confirmed with us, the development of this reference happened in complete secrecy. Without running it past the manufacture’s upper management, a team of watchmakers, comprised of Michel Rochat, Jean-Daniel Golay, and Wilfred Berney, developed a perpetual calendar module that could sit atop the thinnest automatic movement on the market, the JLC 920. The development of the JLC 920 was first led by Jaeger LeCoultre in 1967, with funding and contribution from Audemars Piguet, and was famous for its adoption by all three manufactures from the ‘Holy Trinity’. Because of its reliability and thinness, it was the ideal starting point for designing the world’s thinnest automatic perpetual calendar.

We spoke with Raphaël Balestra, from the Audemars Piguet archives in Le Brassus, who revealed that the movement wasn’t initially supposed to be an automatic one. As he points out, “we had someone in our complications department working on the prototype, in secret, and he showed it to our head of client services. He was very in touch with what our customers were looking for and suggested that he put it on an automatic calibre, as that’s what the people wanted at that time.” From there, they presented their prototype to Georges Golay, the CEO of Audemars Piguet at the time. He was so taken aback by the piece that he instantly asked for 150 pieces to be made. The following year, in 1978, the model was released to the public.

Apart from being the first in the trilogy, the Quantième Perpetuel stands out for being the most experimental of the perpetual calendars released during this period, with the brand producing an incredibly rich array of variations. Not only did it come in a full complement of metals – across yellow, white, rose gold, platinum, and steel – but it also had a staggering amount of dial choices on offer. Other than the classic eggshell white, they also offered dials with mother of pearl, a hand-hammered blue “Tuscan” texture, salmon, as well as an elaborate skeletonised version, just to name a few. In many ways, the creativity we see today from modern Audemars Piguet, can really be traced back to these watches and how they developed through the ‘80s and ‘90s.

We also see some rather interesting variation in the case design, throughout the lifespan of the reference. The design of these models was ultimately the vision one person, Jacqueline Dimier, considered by some to be Gerald Genta’s protégé. Building on the impressive movement, it was her ideas that helped to shape this model into the recognisably classic form we see today. Balestra mentioned that he once had the chance to speak to Dimier about her design. When asked why she’d included the stepped bezel, for example, he said: “she told me it was to make the whole watch look thinner. As she explained, a flat surface will always look bigger.”

Beyond the classic shape, Audemars Piguet also experimented with different types of case designs. For example, they integrated the perpetual calendar movement into their Royal Oak, combining their innovations from 1976 and 1978. With different metal and dial variations created over time, some of the pieces can be particularly visually impressive. They equally designed some pieces with more unusual cases or integrated bracelets, such as the so-called “Clover”, where the case extends onto the top portion of the dial, featuring a clover-shaped sapphire crystal in the centre.

Though the Royal Oak is often credited for helping Audemars Piguet survive in the wake of the Quartz Crisis, evidence suggests that the Quantième Perpetuel played a much greater role. They took a classic complication, updated it for modern times and then used it as the canvas on which to experiment with bold and thoughtful designs, combining the best of the past and the present. According to the manufacture, 7,219 perpetual calendars were made over a fifteen-year period, with around 70 different models being produced and 200 variations documented.

Five years after Audemars Piguet released their innovative perpetual calendar, Vacheron Constantin introduced their own version of the complication – one which could easily be confused for its rival. With an almost identical dial layout, a similar case size, and the same JLC 920 ébauche, the similarities between these two pieces are quite apparent.

Of course, Vacheron Constantin’s tradition of complicated watchmaking stretches much further back. The manufacture was producing perpetual calendars as long ago as 1884, with some of them displaying similar design features to what you can find on their reference 43031, released in 1983. We spoke to Christian Selmoni, the Style and Heritage Director at Vacheron Constantin, who pointed out that, “we had been making calendar wristwatches since the ‘30s, but we didn’t make any perpetual calendar wristwatches until the ‘80s.” As such, the reference 43031 marked the first time that Vacheron Constantin put a perpetual calendar on the wrist, which is rather remarkable. It was also the first time in two decades that the manufacture has produced a calendar watch, of any kind, having sold their last one in the early ‘60s.

Building on the high-quality JLC 920 ébauche, Vacheron Constantin sought the help of complications specialist Dubois-Depraz for the perpetual calendar module. The result was the 1120 QP. Where the Audemars Piguet perpetual calendar only displays the 12 months of the year, without any indication for the leap year, the Vacheron Constantin uses a 48-month sub-dial, allowing the wearer to track what stage of the four-year cycle they’re in. Whilst this does compromise legibility, this approach is highly reminiscent of some vintage pocket watches from their archives, and it is also ultimately more precise.

The remarkable feat of this movement is its longevity. Even though it was introduced in 1983, it still powers the brand’s perpetual calendars today, almost four decades later. Not only does this speak to the quality of this calibre but it also offers some reassurance to collectors that servicing with the manufacture will remain relatively straight-forward for the foreseeable future.

Whereas Audemars Piguet experimented with a wide range of metals, case shapes, and dial designs, Vacheron Constantin were relatively restrained in their approach. The reference 43031 was only ever produced in yellow gold and platinum, with fewer dial variations created over time. As far as we’ve been able to gather, the manufacture only ever produced cream, champagne, or white guilloché dials. The champagne dials only seem to appear on early pieces, whereas the guilloché dials come in towards the end of production.

That being said, Vacheron Constantin did still experiment with their perpetual calendar. In 1984, a year after they released the original model, they came up with a skeletonised version of the design, under the reference 43032. This was made available in yellow gold, with white or yellow subdials, or platinum, with white or blue subdials. The manufacture estimates that around 150 skeletonised watches were produced in platinum, with only 20 of these bearing blue subdials. A handful of pieces were also produced with diamonds on the bezel or dial, an approach which Audemars Piguet also followed, but which Patek Philippe would later abstain from. They also released a watch with a 16-sided case under the reference 43033, which they would also go on to skeletonise. A unique take on this classic timepiece.

There are a few, quite subtle differences, that set the Vacheron Constantin apart from its predecessor, the Audemars Piguet. For example, the moonphase on the former is made from lapis lazuli, a deep blue metamorphic rock, which adds a small spark of colour to the otherwise pared back colour palette. There are also a few minor differences in the length of the hands found on the subdials or the shape of the lugs, which give both watches a slightly different feel on the wrist.

According to Selmoni, the reference 43031 was produced between 1983 and 2006. Due to the complex process of tracking historical records, the manufacture is currently unable to give a firm number of how many were produced over the lifespan of the reference. However, they were able to confirm that production figures did vary quite significantly throughout that period, from around 20 to 100 pieces made per year. If we assume that annual production was always on the upper range, this would imply that Vacheron Constantin produced less than 2,300 of these perpetual calendars over 23 years. Rather surprisingly, this is almost three times less than Audemars Piguet or Patek Philippe ever produced of their own references.

Finally, we come to a model which we’ve covered in quite a lot of depth previously, the Patek Philippe reference 3940. Introduced in 1985, it followed similar pieces from the other two manufactures. As we’ve explored this reference before, we won’t go into too much technical detail. Rather, we thought it would be more interesting to look at it in comparison to the other two.

Despite being the last to be released, with the first 25 pieces selling through Beyer in 1985, it is certainly the one which has received the most attention from collectors in the past. For the design, Patek Philippe took the sub-dials down from four to three, with the leap year indicator being placed inside the months sub-dial at 3 o’clock. The manufacture also added a further 24-hour indicator, which can’t be found on either of the other models.

In some ways, it could be argued that Patek Philippe didn’t have much of a choice but to release a watch such as this one. With the commercial success of both Audemars Piguet and Vacheron Constantin, they needed to create their own version of an ultra-thin, automatic perpetual calendar, if they were to retain their position as one of the foremost producers of complicated wristwatches. As mentioned above, Patek Philippe were also the first to integrate the complication into a wristwatch and also led the way in producing the first automatic perpetual calendar. Being left behind wasn’t an option.

However, Patek Philippe didn’t just release the 3940 in 1985. They combined the launch with its sister reference, the perpetual calendar chronograph, reference 3970. This pair placed them firmly in a league of their own when it came to manufacturing sophisticated complications in series. Furthermore, whereas the other two members of the “Holy Trinity” experimented with some bolder, more contemporary designs, Patek Philippe remained firmly traditional. There isn’t as much dial variation as we see with the previous two – nothing more than cream or champagne, no skeletonised version, and not even a hint of guilloché.

The other major difference that separates this from its two competitors is the movement. The base calibre is the 240, developed by Gérard Berret, technical director at the time, and his team of watchmakers. It is believed that this movement shares some similarities with the Universal Genève calibre 66, with the watchmaker having pioneered technology in micro-rotor movements. Originally used in the Golden Ellipse, Stern pushed for a perpetual calendar module to be developed on top of the 240, despite calls that it was too thin to withstand it. Luckily, Stern was proven right and the 240Q was born. The only one of the three to run on a micro-rotor, it matched the Vacheron Constantin 1120 in achieving the qualities needed to obtain a Geneva Seal.

Despite their similarities, it could be argued that each of these three pieces have their own, distinct identity. The Audemars Piguet was the first, and certainly the most experimental of the three, with its colourful dials and unusual cases. As for Patek Philippe, they very much played the role of the custodian, creating a classic design, with restrained aesthetics and limited variation. As you would expect. Finally, Vacheron Constantin probably sits somewhere in the middle, between experimentation and tradition, though they certainly included details which are distinctively their own, from the lapis lazuli moonphase to the four-year indicator.

Until recently, it would be fair to say that this collection of watches was broadly overlooked by the horological community. They were too new to be considered as important or collectable, and too old to be seen as exciting or innovative. For a long time, they sat in the awkward space which has now come to be described as neo-vintage, lagging far below what their original retail price would have been when they were first sold. For context, the retail prices for these pieces were similar across all three brands, across different metals and variants. For the yellow gold model with a closed dial, the retail price was roughly around USD 80,000, if we adjust for inflation.

However, the gradual discovery of these pieces by the collecting community would seem to follow an interesting route. Patek Philippe, despite being the newest, was the first to grow in market appreciation, although this interest was originally limited to the earlier and rarer pieces. Then, as appreciation for the reference grew more widely, the market value for all the different variants surged, carrying the remainder of the pieces. Following that, it appears that we’re now at a stage where the gap between the “standard” and “special” variants is increasingly widening, such that the latter can sometimes be valued at several times the worth of the former. To give you some context, whilst a standard, yellow gold reference 3940 may fetch around £35,000 today, one of the first 25 pieces, which were sold through Beyer, recently achieved close to £144,000 at auction.

Whilst much of this was occurring, the Audemars Piguet and Vacheron Constantin pieces remained largely ignored, despite having been created earlier and sharing many of the same characteristics. This can largely be attributed to one factor – they weren’t made by Patek Philippe. Indeed, there is no need to remind our readers that the blue-chip brand still carries more clout in the eyes of collectors than the other two, even if things now appear to be changing.

Following the ascendancy of the reference 3940, interest in the Audemars Piguet pieces caught on, as people began to discover their historic role in reintroducing the complication, as well as the endlessly interesting variants on offer. Today, the more unusual versions of the Quantième Perpetuel – such as those carrying a skeletonised or textured “Tuscan” dial – have become particularly sought after. In tandem with this, as with the Patek Philippe reference, all different variants of the Audemars Piguet perpetual calendar have come to gain more appreciation, understanding and, ultimately, value.

As the remaining member of the Trinity, examples from Vacheron Constantin are increasingly attracting interest too, collectors having caught on to the similarities which link the three pieces together. Since these models have traditionally lagged-behind the other two, the market is only now beginning to take shape, though it’s likely that we’ll see things play out in a similar fashion. Ultimately the history, design, and intrigue of the pieces themselves, made us think it would be worth spotlighting this market evolution, as it speaks to the broader context in which trends appear and shape one another. It is however, only part of the picture, hopefully providing a useful insight into what people choose to care about, and when.

We would like to thank Raphaël Balestra of Audemars Piguet and Christian Selmoni of Vacheron Constantin for sharing their knowledge and insight on these timepieces. We would also like to thank Seamus for allowing us to shoot his incredible collection and sharing his thoughts on them.