This Monday, Christie's will hold a sale of important and vintage watches with an excellent range of great brand names on offer, including Breguet, Jaeger-LeCoultre, Audemars Piguet, Omega, Vacheron Constantin, Cartier and especially Rolex (50) and Patek Philippe (91).

The stand out lot by far is expected to be one of these Pateks, on offer for a cool CHF1.5m-2.5m (US$2.23m).

The watch's features include a perpetual calendar chronograph, with moon phases, enclosed in a tonneau-shaped case.

To be precise, it is a watch, completed in 1944, at the eve of World War II's end, which was anything close to the well-behaved peers of the early 1940s production but stood out by its avant-garde case design and proportions - not seen in Patek Philippe's regular production for nearly another decade.

Historically important Patek Philippe

The case body has more roundness than reference 1518 - world's first wristwatch, made in series, featuring a perpetual calendar, moon phases and chronograph, introduced in 1941 - and the lugs have grown in length and are more curved - smoothly clinging around its wearer's wrist.

Thanks to the much more generous use of natural roundings and less of architectural lines, the watch has not only grown in size compared to reference 1518 but also gained a much more sensual appearance.

The historically important, 18K gold piece will lead Christie's sale in Geneva on May 10.

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