Leonidas Watch Factory Calibers

Leonidas Watch Factory was founded in 1841 by Julien Bourquin in Saint-Imier, Switzerland, and grew to become one of the four principal Swiss suppliers of chronograph movements in the mid-20th century, alongside Lemania, Valjoux, and Landeron. The company produced quality lever-escapement watches, extra-thin pocket watches, and precision chronographs. In 1911 the factory was acquired by Constant Jeanneret-Droz, whose son Charles ran it for decades; in 1941 — its centenary — Leonidas began producing observatory-rated chronometers.

In 1964 Jack W. Heuer acquired Leonidas, forming the Heuer-Leonidas entity. During the quartz crisis Heuer-Leonidas was taken over by Nouvelle Lémania in 1982, then sold to the TAG group in 1985, at which point the new entity became TAG Heuer and the Leonidas name was retired. The brand was briefly revived in 2015 as an independent line of mechanical watches. Leonidas vintage chronographs — especially column-wheel calibers from the 1950s–60s — are keenly collected as examples of the classic Swiss chronograph golden age.