and that he had watch movements made there with a value of 90,000 livres a year. As a clock and watchmaker to Louis XV, Louis XVI and Napoleon Bonaparte, Lépine's creations were well respected and in demand. 1764/65: Invention of the revolutionary Lépine calibre Around 1764/65, he devised a means of manufacturing a pocket watch that could be thinner, favouring the onward quest for further miniaturization. His radical design broke with a 300-year tradition and ushered in the age of precision timekeeping, the modern pocket watch was born. In addition to paving the way for the making of even thinner watches, this innovation was readily adaptable as the basic model for mass-producing watch-movements, a process that was to begin in the nineteenth century. Up to the 1840s, watches were all hand-finished, so that parts were not interchangeable. The Swiss, Leschot in particular, believed there was a market for cheaper, machine made watches with interchangeable parts. Refusing the incipient industrialization, French watch making only survived by becoming a peripheral adjunct to the Swiss watch making powerhouse, with only a few isolated Parisian cabinotiers still making truly French watches with French movements. The usual practice in the 18th century was to have the movement between two parallel plates and the balance wheel outside the top plate. The Lépine calibre discarded the top plate altogether and used individual cocks mounted on a single plate. This arrangement made it easier to assemble and repair the pocket watches, but also allowed the balance to be set to one side. Essentially, the "Lépine calibre" or "calibre à pont", served to reduce a watch's thickness. To do this, it exchanged the traditional frame with two bottom plates for a single plate onto which the train is fixed with independent bridges. It also removed the fusee and its chain and then began using the cylinder escapement. He also invented the floating mainspring going barrel. The Lépine calibre uses bars and bridges instead of pillars and upper plates. As mentioned, the movement has no fusee which equalizes the driving power transmitted to the train, replaced instead by a going barrel to drive the train directly. This improvement was facilitated by using the cylinder escapement and enhanced springs. The calibre was quickly adopted throughout France and today its basic design is what characterizes all mechanical watches. It is important to note that the term "Lépine" can refer to both the