Mankind’s first awareness of the passing of time was the transition from darkness to light as the sun moved across the sky. Longer passages of time were defined by regular patterns in the movement of the sun, moon and stars.
The earliest timekeeping devices, used in Ancient Egyptian, Babylonian and Chinese cultures, were sundials (shadow clocks), and clepsydrae (water clocks). Ancient Greek astronomers developed sophisticated models of the universe and invented instruments that reproduced the celestial cycles. The Renaissance brought a new understanding of the universe. Mechanical clocks appeared at the beginning of the 14th century.
Sundial
One of the very first time-telling instruments, a sundial shows the time during daylight hours. It comprises a flat plate marked with hours (the dial) and a gnomon, which casts a shadow onto the dial. As the Sun appears to move across the sky, the shadow marks off the hours. Thanks to this tool, the ancient Egyptians and Babylonians divided daylight into 12 equal parts as the shadow cast by the gnomon moved across a marked scale. Then they divided darkness into 12 equal parts, creating the 24-hour day. However, the length of each hour varied throughout the year: a daylight hour lasted longer in summer than in winter, and a night time hour was longer in winter than summer.
Astrolabe
Over the millennia, instruments have been invented to reproduce the celestial cycles and to enhance scientists’ understanding of astronomical phenomena. Astrolabes – introduced during the Hellenistic period and more widely used from the 8th century onwards – were hand-held models of the universe rendered on a flat surface. By enabling early astronomers to work out the relationship of various cosmic bodies, astrolabes had applications in astronomy, astrology, navigation and religion.
Tellurion
The Renaissance brought a new understanding of the universe. Although a heliocentric model (with the Sun at its centre) had been hypothesised in Ancient Greece by Aristarchus of Samos, the geocentric model (with the Sun and planets revolving around a fixed Earth) prevailed until 1543, when Copernicus published his model of the solar system. Three-dimensional mechanical mobiles known as tellurions (also written “tellurium”) were developed to illustrate the relative positions and movements of the Earth and Moon in relation to the Sun.
The Birth of Watchmaking
Astronomers often had a keen interest in clock-making and it was Galileo who first noticed the timekeeping property of the pendulum – the first “oscillator”. In Europe, mechanical clocks appeared the 14th century, although accurate timekeeping remained elusive. The breakthrough came in 1656 when the Dutch astronomer and physicist Christiaan Huygens invented the pendulum clock. Thereafter, astronomy and horology developed in tandem, one relying on the other.
The Watchmaker of Watchmakers
Driven by a strong spirit of invention, Antoine LeCoultre established his watchmaking business in 1833, setting the standard for what has become an exceptionally well-rounded Manufacture. As horloger-inventors, Jaeger-LeCoultre’s watchmakers have mastered all forms of astronomical complication, from simple moon phase displays to highly complex perpetual calendars and sky charts, translating cosmic phenomena into the tiny confines of a wristwatch case and even combining them with other functions to create Grandes Complications. These remarkable calibres were bought by many other great Maisons for their own watches, hence Jaeger-LeCoultre’s nickname: “the watchmaker of watchmakers”.
