Invention of clock.

In 725 AD, a Chinese monk named Yi Xing developed what one could call the most advanced precursor of the mechanical clock later a French Benedictine monk Gerbert d' Aurillac designed a system of gears run by counter balanced weights. The invention has been attributed as the first mechanical clock in the history of science.

The clock that struck a bell on every hour was recorded in 1,120 in Citeau in France. These were large fixed devices.
Italian architect, Filippo Brunelleschi was the first to introduce the spring - driven clock in 1410 at Florence.

The pendulum based mechanical clock was introduced in 1657 by the dutch inventor and astronomer, Christian Huygens. The near accurate oscillation of the pendulum improved the time accuracy of the mechanical clock.

In 1840, the first electric clock was invented by Scotsman Alexander Bair (1818-1903).

Antoire Radier made the first spring - driven clock in France in 1847.
In 1890, the first electric alarm clock was introduced.