Uncovering the history of timekeeping through archaeological exploration and historic research.

From our humble hunter-gatherer beginnings to the most advanced of ancient civilizations, the sun and moon have always held a particular fascination for humanity. Several forms of tools, monuments, and mechanisms have been created to determine the dates, seasons, and keep the time. However, the specific reasons for this innate need to understand the concept of time still evade us. From sundials and ancient tally marks on 30,000-year-old sticks, to intricate water clocks used in the ancient civilizations of Europe and the Far East, up until the clock as we know it today, the pursuit of accurate timekeeping has been one of the ultimate goals for humankind.

But what exactly is the purpose of comprehending time? Ancient peoples have used time in agriculture and astronomical observation . Even today, our fascination continues as astronomers and physicists work with it to further unravel the mysteries of the universe. These days, time is measured using the sexagesimal system (a numerical system with sixty at its base), as it has been 2000 BC. However, the specific reasons for understanding the importance of time may be more complicated than one would expect. Was the reason agricultural, astronomical or routine? Or, dare we postulate, menstrual? In studying these perspectives throughout the human history of timekeeping, there is hope for an answer. After all, there could be more to time than just timekeeping.

Figurative art, found in a cave in East Kalimantan, Borneo, depicts wild cattle and dates to about 40,000 years ago. Some researchers correlate the position of certain paintings with the position of the stars and the moon.

Lunar Calendars Throughout the Ages

The changes of the Moon phase have held a particular fascination for humanity since the Palaeolithic era, and possibly even before. Studying the moon helped early humans understand the seasons: when to harvest fruit and berries, and when to migrate and hunt animals. One of the first forms of keeping track of the lunar calendar may be found in the 40,000-year-old cave paintings on the island of Borneo, which depict wild cattle and bulls with horns. For a long time, prehistorians and archaeologists believed that cave paintings were ritualistic, representing good fortune for future hunts. However, some researchers have correlated the position of certain paintings with the position of the stars and the moon.

Left; Ishango bone on display at Royal Belgian Institute of Natural Sciences. Right; De Heinzelin’s detailed drawing of the Ishango bone. Researchers have presented various hypotheses to explain its use.

Though shrouded in mathematical mystery, the Ishango bone is one of the earliest mathematical tools found to date, and it may have been used to track time during a six-month lunar cycle. The bone artifact is argued to have been created between 8,000 and 20,000 years ago. It was found in 1960 by Jean de Heinzelin de Braucourt while exploring the then Belgian Congo near the Semliki River. The artifact consists of a baboon's fibula with a piece of quartz attached at one end. Its sides have been scratched with several uniform tally marks that run along the bone in three columns. Various tantalizing hypotheses have been reached by researchers fascinated by the artifact. The most popular explanation is that it was used as a lunar calendar. However other interpretations conclude that the Ishango bone was used to understand and calculate prime numbers.

Stonehenge in England was created sometime between 3000 BC and 2000 BC. Many researchers believe it was used to aid in predicting seasonal changes depending on the position of the Sun. Others speculated that Stonehenge may have been a place for ritual celebration of birth and death. However, since that the culture that built Stonehenge left no written records, these are just hypotheses for why the megalithic monument was created.

Stonehenge is one of the world’s most famous prehistoric monuments. This huge megalithic monument, a unique stone circle, was erected in the late Neolithic period about 2500 BC. There have been many theories on why it was built.

As civilizations advanced, so did the need for better timekeeping methods. Later ancient civilizations, such as the Egyptians and Babylonians, began to pay closer attention to the Sun and Moon rotations. As their cultures grew in size, the need for measuring time became paramount as it began to serve several other functions including social events, harvest cycles, and scheduling of payment and trade. The development of these civilizations related to three cycles: the solar day with its periods of light and dark, the lunar month due to its appearance during the month, and the changing of the seasons.

Ancient Egyptians created advanced solar and lunar calendars. This calendar, found in Kom Ombo Temple, shows hieroglyphics for particular days of the month.

The social impact of the lunar cycle throughout history has depended on the physical location of any given society in relation to the Moon. For many civilizations, especially those who are located closer to the equator, the lunar cycle has had a profound effect. Cultures in the lower latitudes have historically been far more inspired by the lunar cycle than those who relied on the solar year. The Egyptians, for example, developed a lunar calendar consisting of twelve months of thirty days. The months were then subdivided into 10-day periods known as decans. The complex Egyptian method of daily timekeeping was soon adopted by later civilizations such as the Greeks and Romans. At higher latitudes and in northern regions, solar calendars have historically been more essential since the changing seasons were more severe. Planning for seasonal crops became a race against the Sun's dimming and the arrival of the cold.

The Menstrual Perspective: Did Menstruation Create the World?

If studied from a feminine perspective, lunar cycles, and a society’s interpretation of them, can be understood differently. The Ishango bone, for example, has also been postulated to correlate with the menstrual cycle. Claudia Zaslavsky, an American mathematics educator and ethno-mathematician, discusses this in her study of the history of women and mathematics, mentioning the findings of the Ishango bones for their potential use to track a woman’s menstrual cycle. As Zaslavsky states, “who but a woman keeping track of her cycles would need a lunar calendar? […] After all, women most likely discovered cultivation while men were out hunting.”

Zaslavesky has also referenced other calendar bones discovered in Europe dating back as far as 30,000 years. Other authors, such as Dena Taylor and Sue Smith-Heavenrich, authors of The Power of Menstruation , have also mentioned a strong link between ancient women mathematicians and menstrual cycles. They also contemplate the lunar markings found on the Ishango bones as being an ancient lunar calendar correlating to the menstrual cycle. In her book Blood, Bread, and Roses: How Menstruation Created the World , Judy Grahn has also connected the Ishango bone to the female menstrual cycle and the phases of the Moon.

Grahn’s belief in the significant role of the menstrual cycle in relation to the development of timekeeping is based in metaformic theory. This theory, which is based on four hundred years' worth of myths, artifacts, and anthropological data, states that the narrative forms of language, stories, numbers, and sound derived from involvement and associations with life cycles. Metaformic theory is also tied to the belief that lunar calendars and menstruation cycles were intertwined and evidenced in several cultures around the world.

The Hindu goddess Kali, Goddess of Time, Creation, Destruction and Power, is worshiped by Hindus all over the world.

Specific cultural examples highlighted in this theory include the Hindu goddess Kali, the Maya moon goddess Po, and the Latin word menses, which relates to the word “month”. Additionally, Grahm connected further evidence related to menstruation and lunar calendars via the creation of Venus feminine figures, such as the Venus of Willendorf and Venus of Laussel, during the Palaeolithic period of humanity. However, metaformic theory remains a hypothesis at best.

Sundials, Water Clocks, and the Evolution of Mechanical Timepieces

Though timekeeping, and potentially agriculture, may have initially been conducted by women, it is still a controversial hypothesis that timekeeping had to do with their menstrual cycles. In other historic accounts, as human populations moved further into sedentary lifestyles, they needed to develop mathematical techniques to maximize land and human habitation in locations which would become major cities of the ancient world. This evolution contributed to the advancement in methods for timekeeping.

Ancient Egyptian sundial from 13th century BC discovered in the Valley of the Kings in 2013.

The study of lunar cycles was accompanied by the study of sun and shadows. Some of the earliest devices used for telling time were sundials, or shadow clocks. According to archaeological evidence, these were used in ancient Babylonian astronomy and in ancient Egypt . In 2600 BC, China was also using timekeeping instruments such as the sundial in order to measure time and conduct astrological calculations. However, their accuracy was questionable due to the unpredictability of daily weather conditions.

Shortly after the development of both a lunar and solar calendar, ancient civilizations began developing better methods of day-to-day timekeeping. The water clock may have been created by the Zhou Dynasty as early as 1046 BC, and brought to Mesopotamia later on, but these dates are uncertain.

Ancient Persian clock in Qanats of Gonabad Zibad.

In Ancient Greece, Plato is said to have introduced the first water clocks there dating back to the 3rd century BC. They developed a water-powered mechanism called the Clepsydrae. These contraptions were used for several hundreds of years. Another variation of this clock was used as an alarm that relied on the overflow of lead balls falling into a vessel floating over a columnar vat. Over the duration of a day, the vat would fill with water until it tipped over, causing the balls to descend into a copper plate, which created a noise used to awaken Plato's students in the morning. Another water clock, known as the Fenjaan, was developed between the sixth century and third century BC in ancient Persia , and was used for the equal distribution of water to farmers and landowners for irrigation. Over time the FenJaan was used to determine holy days in the Zoroastrian calendar. Water clocks were used continually until the 11th century AD in Europe.

Three different depictions of ancient water clocks, all part of the history of timekeeping.

Timekeeping was also performed using the hourglass, which was used mainly on large maritime vessels in the 11th century. Hourglasses were also used by craftsmen, for prayer, and in flour mills. Compared to the sundial, the hourglass was more consistent and dependable. The Roman Catholic Church was also responsible for additional developments in timekeeping technology, as the precision was needed to indicate the times for prayer in monasteries across Europe. As time went on, the necessity for accurate timekeeping became paramount as trade and merchants began to expand into other regions. One example was the addition of bells to indicate times for prayer. By the 11th century AD in Islamic Iberia, the first geared clock was created by Ibn Khalaf al-Muradi. This additional sophistication to timekeeping influenced the further development of the mechanical clock in Europe.

By the 1580s clockmakers were trying to figure out how to count minutes and seconds to gear clocks in the pursuit of ever-better methods of timekeeping. The measurements and techniques in determining the minutes and seconds were derived from the sexagesimal partitions of degrees. However, the method was not perfected until the creation of the pendulum clock, developed by Christiaan Huygens in 1656. Six months later, Huygens was granted a license for the commercial manufacture of pendulum clocks. In 1675 he further developed watchmaking technology and created the spiral-hairspring watch, which brought with it further precision, and consisted in a balance spring added to the balance wheel. This creation helped lay the foundation for how the modern watchmaking industry would create timepieces.

Further development continued with the creation of the marine chronometer by John Harrison in 1761. Soon after Scottish clockmaker Alexander Bain invented the electric clock in 1850, by employing the use of an electromagnet pendulum and an electric current to replace the spring and weight mechanisms that initially existed in prior clock designs. By 1927, the Crystalline Quartz oscillator was finally incorporated into clocks by Warren Marrison and J.W. Horton at Bell Telephone Laboratories in Canada. This technology for clocks would be used and perfected throughout the 20th century. The atomic clock was built by Louis Essen and Jack Parry in 1955 at England’s National Physical Laboratory. The atomic clock remains the most precise timekeeping device in existence. However, in 1969, the Japanese watch company Seiko was the first to introduce the quartz wristwatch, making this advanced technology available to the masses, thus joining the ranks of other incredible advances within the history of timekeeping.

The Japanese watch company Seiko was the first to introduce the quartz wristwatch in 1969, making this technology available to the masses.

Will We Ever Uncover the Full History of Timekeeping?

With the advent of human consciousness, there has been a continuous fascination with timekeeping: timekeeping has been used by astronomers to keep track of planetary and stellar movements, by sailors to determine longitude over the seas and by farmers to plan irrigation and crop planting through the eons of agricultural history. Even in the modern world, timekeeping and precision are necessary to keep our human civilization advancing into the future, and also one day, towards the stars. However, the origins of timekeeping still remain a mystery. And, who knows, maybe all the timekeeping devices created throughout history really can trace their origins to ancient women tracking their menstrual cycles.