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Stonehenge was ancient solar calendar

Harry Pettit, The Sun, March 7, 2022 7:00PM Kids News

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Researchers believe Britain’s famous stone circle known as Stonehenge was built as an ancient solar calendar. Picture: English Heritage/Visit Britain media_cameraResearchers believe Britain’s famous stone circle known as Stonehenge was built as an ancient solar calendar. Picture: English Heritage/Visit Britain


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The mystery surrounding why prehistoric Brits built Stonehenge looks to have finally been solved after research confirmed the monument served as an ancient solar calendar*.

Professor Timothy Darvill concluded* the site was designed as a calendar based on a solar year of 365.25 days, helping people keep track of the days, weeks and months.

His analysis includes new finds about the stone circle’s history, along with examination of other ancient calendar systems.

Professor Darvill said Stonehenge had long been thought to be some kind of calendar because of the “clear solstitial* alignment*” of its boulders, known as sarsens.

“Now, discoveries brought the issue into sharper focus and indicate the site was a calendar based on a tropical solar year of 365.25 days,” he said.

media_cameraStonehenge’s boulders were believed to have been added to the circle at the same time and were sourced from the same area. Picture: English Heritage/Visit Britain

Recent research showed that all of Stonehenge’s sarsens were added at the same time, around 2500BC.

They were sourced from the same area and subsequently* remained in the same formation. This indicates they worked as a single unit.

Professor Darvill, from Bournemouth University, analysed these stones, examining their numerology* and comparing them to other known calendars from this period.

He identified a solar calendar in their layout, suggesting they served as a physical representation* of the year that helped the inhabitants keep track of the days, weeks and months.

“The proposed calendar works in a very straightforward way,” he said. “Each of the 30 stones in the sarsen circle represents a day within a month, itself divided into three weeks each of 10 days.”

The distinctive stones in the circle marked the start of each week, and an intercalary* month of five days and a leap day every four years were also reflected in the design.

“The intercalary month, probably dedicated to the deities* of the site, is represented by the five trilithons* in the centre of the site,” Professor Darvill said.

“The four Station Stones outside the Sarsen Circle provide markers to notch up* until a leap day.”

This means the winter and summer solstices* would be framed by the same pairs of stones every year.

media_cameraProfessor Timothy Darvill believes the five trilithons are the centre of the site represent an intercalary month of five days. Picture: Charles Miranda

One of the trilithons also frames the winter solstice, indicating it may have been the new year.

This solstitial alignment also helps calibrate* the calendar – any errors in counting the days would be easily detectable as the sun would be in the wrong place on the solstices.

Such a calendar, with 10-day weeks and extra months, may seem unusual today but were adopted by many cultures during this period.

“Such a solar calendar was developed in the eastern Mediterranean in the centuries after 3000BC and was adopted in Egypt as the Civil Calendar around 2700BC and was widely used at the start of the Old Kingdom about 2600BC,” Professor Darvill said.

People watch the sunrise at the northern Winter Solstice celebration at Stonehenge in Wiltshire, England, 22/12/2011. The omens are good that 2012 will be an excellent year, a druid said today, after the sun shone on Stonehenge during a dawn ceremony to mark the winter solstice. One of the most famous sites in the world, Stonehenge is composed of a circular setting of large standing stones set within earthworks, believed to be thousands of years old. media_cameraPeople have been gathering at Stonehenge, before Covid-19 social distancing rules, to mark the winter and summer solstices each year. Picture: AP

This raises the possibility that the calendar tracked by Stonehenge might stem from the influence of one of these other cultures.

The research, called Keeping time at Stonehenge, was published in the journal Antiquity.

Scientists have argued for decades about the purpose of Stonehenge, with theories including that it was built for sacrificial ceremonies or possibly as an early calendar.

This story was first published on The Sun and is republished with permission.


  • solar calendar: a calendar with dates that are based on the position of the earth and its closeness to the sun
  • concluded: arrived at a judgment or opinion after examining the evidence
  • solstitial: to do with the solstice, which is when the position and tilt of Earth relative to the sun results in the most or least amount of daylight in a single day
  • alignment: when two or more things are positioned in line
  • subsequently: after a particular thing has happened, afterwards
  • numerology: the study of numbers and the belief they might have special meaning or influence on people’s lives
  • representation: the way something is shown
  • intercalary: the addition of an extra day or month in a calendar so that it matches the solar year when the Earth makes one revolution around the sun
  • deities: gods or goddesses
  • trilithons: structures that have two upright stones and a third stone across the top
  • notch up: count, record
  • solstices: the two times of the year – summer and winter – when the position and tilt of Earth relative to the sun results in the most or least amount of daylight in a single day
  • calibrate: correct or adjust something that is used to measure something else


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Solving the Stonehenge mystery


  1. Why does Professor Timothy Darvill believe Stonehenge was built
  2. How many days does a solar year have?
  3. What year were Stonehenge’s sarsens thought to have been added?
  4. How many stones are in the sarsen circle?
  5. How many days made up a week according to the Stonehenge calendar?


1. Compare and contrast
Use a Venn diagram to compare and contrast the ancient solar calendar reflected in Stonehenge’s design to the Gregorian calendar that is widely used across the world now. Your work should identify as many similarities and differences as you can notice between the two calendars.

Time: allow 20 minutes to complete this activity
Curriculum Links: English; History; Mathematics

2. Extension
There are other ways to measure time. One of these is the Chinese Lunar Calendar. See if you can research and write down three facts about this calendar.

Time: allow 15 minutes to complete this activity
Curriculum Links: English; Intercultural Understanding

Wow word recycle
There are plenty of wow words (ambitious pieces of vocabulary) being used in the article. Some are in the glossary, but there might be extra ones from the article that you think are exceptional as well.

Identify all the words in the article that you think are not common words, and particularly good choices for the writer to have chosen.

Select three words you have highlighted to recycle into your own sentences.

If any of the words you identified are not in the glossary, write up your own glossary for them.

Find a bland sentence from the article to up-level. Can you add more detail and description? Can you replace any base words with more specific synonyms?

Down-level for a younger audience. Find a sentence in the article that is high level. Now rewrite it for a younger audience so they can understand the words without using the glossary.

Extra Reading in history