Truly a monumental model, reference 1518 was the first perpetual calendar chronograph wristwatch ever produced in series when it was introduced in 1941, in the midst of World War II. According to research, only 281 examples were manufactured in yellow and pink gold with a few rare examples in stainless steel until the reference ceased production in 1954. Not only did it set the design elements used by Patek Philippe in all of its subsequent perpetual calendar chronograph wristwatches, but in its own manner greatly contributed to the manufacturer's dominant position in the watchmaking industry. It paved the way for successors such as the references 2499, 3970, 5970 and finally, 5270, which features an in-house movement.

Over its course of production, the ref. 1518 can be broken up to specific batches that were manufactured over the years. It is estimated that:

1941 – 1942 = 18 examples made
1943 – 1944 = 36 examples made
1945 – 1946 = 36 examples made
1947 – 1948 = 60 examples made
1949 – 1950 = 56 examples made
1951 – 1953 = 75 examples made

Out of the 281 examples of the reference manufactured combining both yellow and pink gold examples, it is believed that 215 examples were encased in yellow gold with 58 examples made in pink gold and 4 known in steel.

Featuring a 35mm diameter Calatrava inspired case, gold cases were made by master casemaker Emile Vichet identifiable via key no. 9. While its features slightly differ from early (1941 – 1945) to later (1946 – 1953) examples, early cases feature a flatter appearance with a smaller crown and the positioning of the pinholes was slightly higher. Later examples of the reference had lugs that were slightly more tapered, the crown is larger and the chronographic pushers sit lower than ones seen in earlier examples. Often fitted with a silvered dial with applied gold Arabic and dotted numerals, the dials were manufactured by Stern Frères featuring hard enamel graphics with an enamel moon phase handcrafted by the skilled artisans at the firm. Early examples manufactured from 1941 – 1945 were inscribed with long signatures while later examples starting from 1946 featured short signatures.

The present example Patek Philippe ref. 1518 in yellow gold from 1949 is a stunning piece. Boasting an attractive dial with an Italian calendar, the graphics are retained with the accent above the “E” of “GENEVE” still present and clear. The case is nice with thick and balanced lugs with two hallmarks visible one stamped on the caseband and the other beneath the top right lug. Delivered with a Patek Philippe Extract from the Archives confirming the production of the present timepiece in 1949 and its subsequent date of sale two years later in 1951, it is the second time that the present example is being offered at auction. Preserved in the same state as it was offered before, the Patek Philippe ref. 1518 is more than just an addition to a collection but a special piece that certainly defines it.