Accompanied by Patek Philippe Extract from the Archives confirming production of the present watch in 1939 and its subsequent sale on 27 December 1940. It has never been offered in public before.
Reference 521 was in production from 1937 until the early 1940s. The present watch is thought to be the first example of this reference in yellow gold to appear in public to date. It furthermore impresses by its excellent overall condition and freshness to the market.
The modern, yet typical Art Deco style case was designed to fit around the wrist and is also called "Railway" because of its aerodynamic look and the stepped sides.
Although, according to Patek Philippe's archives, the present watch was sold with a leather strap, the gold Gay Frères bracelet can be dated from the same period and was most certainly added upon purchase of the present watch.