Jean-Aimé Jacob was one of the most important French horlogists of the second half of the nineteenth century. He specialized in precision clocks. Born in Sisteron, he moved to Paris at a relatively young age and began working in the workshop of Pierre-Louis Berthoud in April 1813. Several months later, after the death of Berthoud, his widow asked Jean-François-Henri Motel to continue running the workshop. Jacob remained with Motel for several years, then entered the workshop of the renowned horologist Abraham-Louis Breguet in April 1816. After a remarkable Parisian career during which he was awarded several gold and silver medals at Exhibitions of the Products of French Industry, around 1840 Jacob decided to open a workshop in Saint-Nicolas d’Aliermont, a city that was considered a center of horological excellence. He very quickly won recognition for his inventiveness and well-finished creations. He became famous for his chronometers, chronographs, and compensation regulators, having invented several important technical improvements. After having received the title of Chevalier de la Légion d’Honneur in November 1859, Jean-Aimé Jacob appears to have progressively retired; he died in Dieppe on January 30, 1871.