Started As Frères Baume in 1830 in Geneva, by brothers Louis-Victor and Célestin Baume, the manufacturer later partnered with Paul Mercier in 1918, becoming the Baume & Mercier we know currently. During a particularly hard period of time for the model, Baume & Mercier joined the Richemont team in 1988. https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/