The history of the time telling device can be traced to Antiquity. Vitruvius reports that the ancient Egyptians used clepsydras, a time mechanism run by flowing water.
By the 9th century AD a mechanical timekeeper had been developed that lacked only an escapement mechanism. There is a record that in 1176 Sens Cathedral installed a “horologe” – the word still used in French for large clocks. It is derived from the Greek hora meaning hour and legein meaning to tell. This word has led scholars to believe that these earliest timekeepers did not employ hands or dials, but “told” the time with audible signals.
The earliest reasonably accurate clocks are the 13th century tower clocks probably developed for (and perhaps by) monks in Northern Italy. These were used to announce the canonical hours or intervals between set times of prayer. Canonical hours differ in length, and varied as the times of sunrise and sunset shifted.
The earliest clocks that survive in any quantity are mid-16th century table clocks from the metalworking towns of Nuremberg and Augsburg. These clocks have only one hand. The dial between the hour markers is divided into four equal parts making the clocks accurate only to within 15 minutes.
The next major development in accuracy occurred in 1657 with the invention of the pendulum clock. Galileo had the idea to use a swinging bob to propel the motion of a time telling device earlier in the 17th century.
Christiaan Huygens, however, is usually credited as the inventor. He determined the mathematical formula that related pendulum length to time (99.38 cm/39 in. for the one second movement) and had the first pendulum driven clock executed.
In 1670, the English clockmaker William Clement created the anchor escapement, an improvement over Huygens’ crown escapement. The excitement over the pendulum clock attracted the attention of artisans and designers resulting in a proliferation of clock forms.
Notably, the longcase clock (aka grandfather clock) was created to house the pendulum and works. The English clockmaker William Clement, inventor of the anchor escapement, is credited developing this form in 1670.
It was also at this time that clock cases began to be made of wood and clock faces to employ enamel. Modern clocks define constant units of time: an hour is always sixty minutes, of sixty seconds each.
Parts of this article was sourced from wikipedia.com