How Did People Tell Time Before Clocks?

Try a small experiment: put your phone in a drawer for a day and see how long it takes before you want to know the time. For most of human history, nobody had a ticking device on the wall, let alone on the wrist. Yet people still met for markets, held court, prayed together and set sail on schedule. So how did they do it?

The answer is a wonderful parade of gadgets, each built on the same simple trick: find something that changes at a steady rate, and watch it. Here is a tour, roughly from oldest to newest.

1. Shadow sticks: the original clock

The simplest timekeeper is a stick in the ground. As the sun crosses the sky, the stick's shadow swings around and changes length. It is shortest around midday, longest at dawn and dusk. Anyone could read it roughly, and the vertical stick, known later by the Greek word gnomon, is the ancestor of every sundial.

Ancient Egyptians developed portable shadow clocks, including L-shaped devices with marked bars that were turned to face the sun. They gave a rough sense of the hour, which was all most people needed.

2. Sundials: shadows with a scale

Add a carefully marked face to the shadow stick and you have a sundial. Greek and Roman builders made them in astonishing variety: flat, bowl-shaped, cone-shaped, carved into walls and set on columns. Getting one right required real astronomy, because the sun's path changes through the year and depends on where you are on Earth.

The Romans loved them so much that there is a well-known story of a sundial brought back as war plunder from Sicily and set up in Rome, where it apparently told the wrong time for years because it had been designed for a different latitude. Sundials had two obvious weaknesses, of course: clouds and night.

3. Water clocks: time that drips

To keep time without the sun, people turned to water. A water clock, or clepsydra (Greek for something like water thief), measures time by water flowing into or out of a container at a controlled rate. Marks on the inside show how much time has passed. One of the oldest surviving examples comes from Egypt, from around the reign of Amenhotep III in the 1300s BCE.

My favourite use comes from classical Athens. In the law courts, speeches were timed with a water clock: a pot of water drained through a small hole, and when it ran dry, your time was up. If someone read out a document or witness statement, the flow could be stopped so it did not eat into the speaker's allowance. Imagine making your case for your property, or your life, while listening to the water run out.

Later engineers made water clocks far more elaborate. The Greek inventor Ctesibius of Alexandria is credited with improving their accuracy, and in China, Su Song's great astronomical clock tower, completed in the late 1000s CE, used a water-driven mechanism to turn an armillary sphere and ring bells and drums.

4. Candle clocks: burning by the inch

If wax burns at a fairly steady rate, a marked candle becomes a clock. Candle clocks with evenly spaced lines turn up in several cultures, and in England they are associated, through a medieval biographer, with King Alfred the Great, who is said to have used candles to divide his day between duties. Some candle clocks had small nails pushed into the wax, which dropped onto a metal tray with a clink as each section melted. An alarm, of sorts.

Their weakness was the draught. A breeze could speed the flame, so they were often shielded inside lanterns.

5. Incense clocks: time you could smell

In China and later Japan, incense served the same purpose with extra charm. Powdered incense was laid in a pattern, often a winding maze, inside a tray, and lit at one end. As it smouldered steadily along the path, it marked time. Some designs used different scents for different sections, so you could in principle tell the hour by smell. Others hung threads with small weights across the path, which fell into a dish when the incense burned through them.

In Japan, burning incense was even used to measure the time spent with entertainers, a reminder that timekeeping was often about fair billing as much as about schedules.

6. Hourglasses: sand at sea

Sandglasses appear clearly in European records from around the 1300s. They had a big advantage over water clocks for sailors: sand does not slosh or freeze in the same way, and a sealed glass keeps working on a rolling deck.

On ships, sandglasses timed the watches, the shifts of the crew. Short glasses were also used to measure speed: sailors threw a knotted line overboard and counted how many knots ran out while a small glass emptied. That is why speed at sea is still measured in knots. For more of these leftovers, see our piece on the strange origins of everyday measurements.

7. Church bells and the canonical hours

For many people in medieval Europe, time was something you heard rather than saw. Monasteries followed a cycle of prayers through the day and night, known as the canonical hours, with names like Matins, Prime, Terce, Sext, None, Vespers and Compline. Bells rang to call monks to each one, and the surrounding towns and fields used those same bells to organise work, meals and markets.

There is a lovely linguistic fossil here. None was originally the ninth hour of daylight, mid-afternoon. Over time, the service drifted earlier, and the word is thought to be the root of the English noon, which ended up at midday.

The surprise: hours that stretched and shrank

Here is the detail that most surprises people. For much of history, an hour was not a fixed length. Many ancient and medieval systems divided daylight into twelve equal parts, whatever the season, and night into twelve more. In summer the days were long, so each daylight hour was long. In winter, the daylight hours shrank.

These are often called temporal or seasonal hours. They made perfect sense for people who worked by sunlight: the sixth hour was always the middle of the day. But they made life hard for clockmakers. Some water clocks had adjustable scales or replaceable markings for different months. Equal hours were used by astronomers, but they only became normal for daily life after mechanical clocks spread.

Calendars carry similar fingerprints of the sky and of tradition. If you want to know why the week ended up the length it did, read why a week has seven days.

Then came the mechanical clock

Mechanical clocks driven by falling weights and regulated by a device called an escapement appear in Europe around the end of the 1200s, often in monasteries and cathedrals. Early ones were not very accurate and many had no dial at all. They simply struck a bell. (The word clock is related to words for bell in several languages.)

Still, they changed everything slowly and profoundly.

• Work: towns could set fixed working hours, and employers and workers could argue about time in equal units.
• Prayer: religious timetables became tied to a mechanism instead of the sun.
• Cities: public clock towers became symbols of civic pride, and everyone within earshot shared the same hour.
• Science: precise, equal time paved the way for later accurate measurements in astronomy and navigation.

Even then, each town kept its own local time based on the sun overhead. Standardising time across whole regions only came with railways in the 1800s, a story we tell in why time zones zigzag.

What the old clocks still teach

It is easy to see these devices as primitive. I think they are the opposite: clever, local and deeply tied to how people lived. A shepherd's shadow stick, a judge's water pot, a sailor's sandglass, a monk's bell: each solved the problem the user actually had.

If this kind of everyday history is your thing, there is plenty more across our topics. And for a story about how one great technological shift ended an age, our Turning Points feature puts you inside a few of history's decisive moments.