Patek Philippe, Calatrava, "Steel Borgel Case", ca 1940.

Introduced in 1932, the ref. 96 was the first serially produced Patek Philippe wristwatch launched under Jean and Henri Stern after their acquisition of the manufacture, setting the blueprint for the Calatrava line and, by extension, modern dress-watch design.

The example offered here dates to circa 1940 and is cased in stainless steel, a configuration far less common than precious metals and especially prized by today’s collectors. Patek’s steel Ref. 96 cases were supplied by Taubert & Fils, the Geneva casemaker that had acquired François Borgel in 1924 and continued to use the famed F.B in a key hallmark. Their steel work and water-/dust-resistant case engineering (descended from Borgel patents and later Taubert innovations) made them the go-to partner when Patek began offering stainless-steel wristwatches in the 1930s.