An extremely rare and historically important Patek Philippe Ref. 1518 in stainless steel, featuring moon phases, applied applied arabic hour markers, tachymeter scale and bracelet

In 1941, during the turmoil of World War II, a small but momentous event took place in Basel, Switzerland, which forever changed Swiss watch manufacturing. It was at the Swiss Watch Fair Basel (today Baselworld) that Patek Philippe introduced what was a revolutionary wristwatch – the reference 1518.

© Dr Crott Consulting SARL

It was the first perpetual calendar chronograph wristwatch ever produced by any brand in series, and in those uncertain times, demonstrated the brand's remarkable courage. Now considered an important milestone watch in horological history, the reference 1518 set the course for Patek Philippe's dominance in the world of high-end Swiss watchmaking. So ahead of its time was its design, Patek Philippe continued to use its timeless aesthetic as the foundation for a long line of successful and highly sought-after complicated wristwatches, including the references 2499, 3970, 5970 and, 75 years later, even today's 5270.

Patek Philippe produced 281 examples of the 1518 with the vast majority encased in yellow gold. Approximately 55 versions in rose gold are estimated to have been made, and in the rarest and most elite stainless steel version, only four examples are known. The dials had a modern and highly legible layout with day and month apertures at the 12 o'clock position, two subsidiary dials for the 30-minute register and constant seconds at the 3 and 9 o'clock positions respectively. A delightful, oversized moon phase indicator combined with date indication was placed at the 6 o'clock position. The outer edge of the dial featured a raised, hard enamel tachymeter scale.

The incredible stainless steel 1518 wristwatch, of which only four in total are known, is...appearing at auction for the very first time in this sale.

Details of the Patek Philippe Ref. 1518 in stainless steel

Along with variations in the hour markers, Patek Philippe changed their hard enamel signature afer World War II from the long format "Patek Philippe & Co." to a shortened form removing the "Co.". In addition to the long format signatures, early dials featured larger weekday and month apertures, which had less angled framed facets, and a squeezed tachymeter scale with smaller calibrations.

The masculine 35mm diameter case was the epitome of mid-20th century modern design with classic clean lines and extended downturned lugs. The architecture of the simple case never changed, but Patek Philippe made subtle modifications over the course of its production. Early cases were thick with a narrow band, and the chronograph pushers centered on the band, with the date correctors placed closer to the upper edge. Later cases became thinner with a more prominent bezel, and both the chronograph pushers and date correctors were moved to the lower edge.

With its classic style, elegance and state-of-the-art innovations, owning one is considered a summit for collectors of vintage complicated Patek Philippe wristwatches.

Today, the reference 1518 is an icon. With its classic style, elegance and state-of-the-art innovations, owning one is considered a summit for collectors of vintage complicated Patek Philippe wristwatches to achieve – a privilege enjoyed by only a very fortunate few.

We are thrilled to have been given the opportunity to offer not just one such rare timepiece, but an unprecedented trilogy of exemplary examples. It is an unprecedented and truly generational event with the inclusion of the mythical, hardly ever-seen stainless steel reference 1518. Each example is a window into the past, and at no other time in history has a yellow gold, pink gold and stainless steel version appeared in public at simultaneously. Furthermore, we're extremely honored that our private collectors have entrusted us with the sale of their cherished timepieces, having chosen this moment to hand over their stewardship to a new generation of passionate connoiseurs.

Each reference 1518 offered here is in exceptional condition with pristine cases and stunning original dials. These are wristwatches that have become valued as works of art, transcending beyond their functional intent, based on their exclusivity, and 21st century connoisseurship where originality is paramount.

The Patek Philippe Ref. 1518 in yellow gold

The dial of the yellow gold 1518 has a crisp hard enamel signature on the dial with warm tones throughout. The pink gold version is a must-have for any serious collector, with its superb provenance, formerly belonging to H. H. Windsor, the son of the founder of Popular Mechanics magazine. Fresh to the auction market, the incredible stainless steel 1518 wristwatch, of which only four in total are known, is the first of the group to be produced, yet the last to appear at auction, appearing for the very first time in this sale. Manufactured in 1943, this wristwatch can be considered the ultimate summit to achieve for the most experienced collectors.

The Patek Philippe Ref. 1518 in pink gold

This pivotal reference looks as modern today as it did over seven decades ago. Without any doubt, all three 1518s offered in this sale rightly deserve to stand at the pantheon of "all-time greats" of Swiss watchmaking.