Pierre Le Roy

Pierre Le Roy was a French clockmaker. He was the inventor of the detent escapement, the temperature-compensated balance and the isochronous balance spring. His developments are considered as the foundation of the modern precision clock. Le Roy was born in Paris, eldest son of Julien Le Roy, a clockmaker to Louis XV who had worked with Henry Sully, in which place Pierre Le Roy succeeded his father. He had three brothers: Jean-Baptiste Le Roy (1720-1800), a physicist; Julien-David Le Roy (1724–1803), an architect; and Charles Le Roy (1726–1779), a physician and encyclopédiste.