Truly an archetypal model, reference 1518 was the first perpetual calendar (with moonphases) chronograph wristwatch ever produced in series when it was launched in 1941, in the midst of World War II - a bold timing to say the least. According to research, only 281 examples were manufactured, in yellow and pink gold and a few examples in stainless steel, until the reference ceased production in the early 1950s. Not only did it set the design elements used by Patek Philippe in all of its subsequent perpetual calendar chronograph wristwatches down to today’s ref. 5270, but in its own manner greatly contributed to the manufacturer's dominant position in the watchmaking industry. Consider for example that no other company achieved a serial production of similarly complicated pieces until the 1980s. Its successors are references 2499, 3970, 5970 and finally 5270, which features an in-house movement - this make the present line of watches the only one with ongoing production at Patek Philippe since the 1940s.

In production from 1941 until the early 1950s, the case of the model was made by Vichet - one of the historical Patek Philippe case suppliers, most famously employed also for the earliest examples of references 2499 and 2497. Early versions feature the chronograph pushers placed further back on the band, closer to the case back; second series cases, introduced in 1945, instead feature pushers more centrally aligned. The present piece is a not only a very attractive representative of the second series but furthermore one of the earliest examples of this design, as it was manufactured in 1945: the very year of the introduction of the second series.

The present watch is a very well-preserved specimen, displaying good proportions throughout. The dial most notably displays a long signature - absolutely correct for the serial number. As an even nicer touch, the timepiece is accompanied by a thick and fluid Patek Philippe bracelet, also stamped with the long Patek Philippe signature. It gives an incredible presence on the wrist, allowing the owner to "dress up" his or her timepiece for any flamboyant occasion.

Last, but most definitely not least, the importance of its absolutely remarkable set of accessories cannot be overstated. The presence of its original warranty Certificate is already sensational: only a very slight minority of the known 1518 examples survived through their 80 years of life together with the document. But the present piece pushes the boundary even further and comes accompanied by the original 1945 Patek Philippe catalogue and price list - both of them extremely collectable items on their own - two original instruction leaflets, documents detailing the service it underwent in the 1980s, and multiple Extract from the Archives.