c. 1275 – 1700
Who invented the mechanical clock?
No single inventor is known. Weight-driven mechanical clocks appeared in Europe around 1275–1300, built around the verge escapement, which lets a falling weight turn the gears in regular ticks. Early tower clocks struck a bell rather than showing a face. In 1656 Christiaan Huygens built the first pendulum clock, improving accuracy from about 15 minutes a day to about 15 seconds.
Key facts
| First mechanical clocks | Europe, about 1275–1300 |
|---|---|
| Key invention | Verge and foliot escapement |
| Word origin | 'Clock' from Medieval Latin clocca, 'bell' |
| Oldest working clock (claimed) | Salisbury Cathedral, about 1386 |
| Spring-driven portable clocks | 15th century; early watches about 1510 |
| First pendulum clock | Christiaan Huygens, 1656 |
| Accuracy jump | ~15 minutes/day → ~15 seconds/day |
The mechanical clock may be the most important machine of the Middle Ages. It turned time from something you watched in the sky into something a machine produced, in equal pieces, day and night.
Why monasteries cared
Benedictine monks prayed at fixed hours through the day and night. Waking a monastery for night prayers by guesswork wasn't good enough, and the bell-ringer needed a reliable signal. The earliest mechanical clocks of the late 1200s appear in this world of churches and monasteries, and they were mostly alarms and bell-strikers, not dials. The English word "clock" comes from the Medieval Latin clocca, meaning bell.
The escapement
A falling weight provides plenty of power, but left alone it just spins the gears and crashes to the floor. The breakthrough was the verge escapement: a toothed crown wheel turned by the weight is blocked, then released, one tooth at a time, by two small paddles on a rocking rod. A horizontal bar with adjustable weights, the foliot, sets the speed of the rocking. The result is a steady tick, with the weight's energy released in small, equal steps. Every mechanical clock since has some kind of escapement.
These early clocks were not very accurate, gaining or losing perhaps 15 minutes a day, and had to be reset by sundial. But they kept going at night and through winter, and they ticked at one rate, which pushed society toward equal hours instead of seasonal ones.
Clocks go public
By the 1300s, towns competed to build public clocks. Richard of Wallingford designed an elaborate astronomical clock at St Albans Abbey in the 1330s, and Giovanni de Dondi completed his planetary Astrarium in Padua in 1364. The clock at Salisbury Cathedral in England, from about 1386, is often called the oldest working mechanical clock in the world. Merchants, guilds and workers began to organize their days by the town bell.
Springs and watches
In the 1400s, coiled springs replaced weights, making clocks small enough to move. Early portable clocks and the first watches, associated with Nuremberg locksmith Peter Henlein around 1510, were status symbols more than precise instruments, and usually had only an hour hand.
The pendulum
Galileo noticed that a pendulum's swing takes about the same time whether it swings wide or narrow. In 1656 the Dutch scientist Christiaan Huygens built the first pendulum clock, and accuracy improved dramatically, from about a quarter of an hour a day to around 15 seconds. The anchor escapement (about 1670) and the long "grandfather" case followed, and clocks finally became accurate enough to justify a minute hand, and later a second hand.
The pendulum had one weakness: it doesn't work on a rolling ship. That problem would cost thousands of lives before it was solved.
Questions people ask
When was the first mechanical clock made?
Around 1275–1300 in Europe. No individual inventor is recorded.
Why did early clocks have no hands?
The first mechanical clocks struck a bell on the hour. Dials came later, and minute hands became common only after the pendulum made clocks accurate enough in the late 1600s.
What is the oldest clock still working?
The Salisbury Cathedral clock in England, from about 1386, is usually cited. Wells Cathedral and Rouen also have very old working clocks.
Sources
Last updated October 18, 2026. Found an error? Tell us.