When Time Began: A History of Timekeeping

Chronometry, has become a centuries-old race to develop better and more accurate ways of answering the question, What time is it?

Clocks regulate modern existence. Our days are packed with activities and obligations that require us to be in a particular place at a certain time. As a result, chronometry, or the science of timekeeping, has become a centuries-old race to develop better and more accurate ways of answering the question, “What time is it?”


Early agriculturalists during the Neolithic era developed season-oriented calendars to guide crop planting. These timekeeping structures tended to be megalithic and were used to track days, solar years, and lunar activity.

It has been speculated that Stonehenge is one such calendar, as the sunrise solstice can be seen between its two most eastern pillars on June 21 (the longest day of the year). On December 21, the shortest day, the sunset solstice is visible from between the opposite set of stones.

Stonehenge aerial view
Valuable Monuments, Wiltshire, UK, Stonehenge aerial view

In 2013 a Mesolithic arrangement of an arc and twelve pits was discovered in Aberdeenshire, Scotland. It dates to approximately 10,000 years ago and is believed to have been a type of lunar calendar. Archaeologists believe that it is the world’s oldest known calendar.


When complex human societies evolved, with hierarchical governments and long-distance trade, keeping records became important. As a result, time needed to be broken down into smaller units.

People in Central America, Egypt, Mesopotamia, India, and China started numbering the years, transforming chronometry from nature-based cycles into a linear phenomenon. When the Hebrews introduced seven-day weeks and the Babylonians and Chinese divided days into hours, any remaining links between timekeeping and nature were broken. An alternate form of measurement appeared in the form of clocks.

The earliest clocks used natural elements such as sunlight, water, and sand to log the hours. As technology progressed, springs, gears, quartz, and even electromagnetic waves associated with the internal workings of atom powered clocks and improved their accuracy.


The ancient Egyptians were the first to divide their days into something resembling hours. Around 3500 BC, they built four-sided monuments called obelisks, whose sun-directed shadows allowed people to divide the day into two parts (before and after noon). Later obelisks had markers around their base, measuring time in more precise increments.

Rendering of Obelisks at Contra Temple. Photo Credit: UCLA


Building upon the success of the obelisks, the Egyptians developed the more accurate sundial, or ‘shadow clock’, circa 1500 BC. These devices were divided into 10 daylight sections, with allowance for two twilight hours. Because they only kept time for half a day, they had to be turned 180 degrees at midday to chart the afternoon hours.

Ancient sundial
Ancient Sundial. Photo credit: guardianlv.com

Water clocks

Clepsydras, or water clocks, appeared in Egypt around 1400 BC. Devised as a cloudy-day timekeeping solution, they worked by allowing water to flow along a tube from a higher container into a lower one, which was marked by with rings. Each time the water level reached a new ring, it meant that another hour had passed.

Persian water clock
Persian water clocks were a practical and useful tool for the qanat’s shareholders to calculate the length of time they could divert water to their farm.

Sand Clocks

Also known as hourglasses, sand clocks came into vogue during the 14th century, when Europeans began sailing to all four corners of the earth. Rocking ships made the water clocks inaccurate, so mariners embraced this sand-driven timekeeper.

Sand clocks consisted of two connected glass bulbs, positioned so that the top’s contents could trickle down to the bottom. When the top bulb was empty, it meant that a certain amount of time had passed. Sand clocks could be designed to measure various lengths of time, although few ran for more than an hour.

Sand Clock

Mechanical clocks

The future pope, Sylvester II, invented the first completely mechanical clock in 996, but it wasn’t until centuries later that the technology was widely embraced. Mechanical clocks remained the exclusive property of the church for so long because they were seen as essential to maintaining the strict work and prayer schedules that religious institutions followed.

These clocks had intricate (and, for the era, ingenious) gear and wheel arrangements that were turned by attached weights. A pointer attached to the wheels marked the hours. They were eventually engineered to strike the hour and even chime the quarter-hour.

Mechanical Clock Movement

Pendulum clocks

The next breakthrough in the science of timekeeping took place in 1656, when Christian Huygens, a Dutch astronomer, acted on the Galileo’s theory that a swinging pendulum could power a clock. He devised a wood-encased clock with a short pendulum that beat several times per second.

First pendulum clock
First pendulum clock. Photo credit: timetoeatthedogs.com

This new invention had an error of less than one minute per day, which was a big improvement over earlier mechanical clocks. In 1670, British clockmaker William Clement created the grandfather clock by using a longer pendulum and added a minute hand, as time could now be measured by the second.

Wrist watches

The Guinness Book of Records states that the first wrist watch was designed in 1868 for the Countess Koscowicz of Hungary. The concept didn’t really catch on, because these ‘bracelet watches’ were seen as women’s jewelry.

First wrist watch
First wrist watch designed for the Countess Koscowicz of Hungary

When WWI arrived, however, soldiers were equipped with wrist watches to synchronize their movements during maneuvers. These ‘campaign watches,’ now heralded as appropriately masculine, have been worn ever since.

Quartz clocks

During the 1920s, Warren Marrison and J.W. Horton at Bell Telephone Laboratories discovered that quartz crystal generates a consistent frequency. Inspired, they built in the first quartz clock in 1927. Today, quartz is used to power clocks, watches, computers, and other appliances that have an integral timekeeper.

Quartz clock movement
Inside of a quartz clock movement from Klockit.

Atomic clocks

The first atomic clock, which used atom frequencies to keep time, was invented in 1949 at the National Bureau of Standards (now the National Institute of Standards and Technology). It was so accurate compared to other timekeeping solutions that more research was devoted to atomic clock development.

In 2014, a new strontium atomic clock was unveiled at JILA, a joint institute of the University of Colorado Boulder and NIST. Its performance is so precise that it can allegedly keep perfect time for 5 billion years. This clock presently serves as the time and frequency standard for the United States.

JILA's atomic clock
JILA’s experimental atomic clock based on strontium atoms held in a lattice of laser light is the world’s most precise and stable atomic clock.

2 thoughts on “When Time Began: A History of Timekeeping

  1. Randy Sharp June 23, 2015 / 10:18 am

    I love articles like this! The history and evolution of an item, with a brief and general description of each progression makes for an interesting and well-written piece.

    The reader is given just enough information to peak his curiosity to learn more.

    Thanks for sharing this short history on clocks!

  2. Bob Leuci Sr July 20, 2015 / 11:11 am

    Great, short, and very interesting. You gave me enough info that now I want to
    go further and learn more about how it evolved during ancient times, and what
    things and how they were used. Thank you

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