Tag Archives: origin
Why are there seven days in a week? – Henry E., age 8, Somerville, Massachusetts
Waiting for the weekend can often seem unbearable, a whole six days between Saturdays. Having seven days in a week has been the case for a very long time, and so people don’t often stop to ask why.
Most of our time reckoning is due to the movements of the planets, Moon and stars. Our day is equal to one full rotation of the Earth around its axis. Our year is a revolution of the Earth around the Sun, which takes 365 and ¼ days, which is why we add an extra day in February every four years, for a leap year.
But the week and the month are a bit trickier. The phases of the Moon do not exactly coincide with the solar calendar. The Moon cycle is 27 days and seven hours long, and there are 13 phases of the Moon in each solar year.
Some of the earliest civilizations observed the cosmos and recorded the movements of planets, the Sun and Moon. The Babylonians, who lived in modern-day Iraq, were astute observers and interpreters of the heavens, and it is largely thanks to them that our weeks are seven days long.
The reason they adopted the number seven was that they observed seven celestial bodies – the Sun, the Moon, Mercury, Venus, Mars, Jupiter and Saturn. So, that number held particular significance to them.
Other civilizations chose other numbers – like the Egyptians, whose week was 10 days long; or the Romans, whose week lasted eight.
The Babylonians divided their lunar months into seven-day weeks, with the final day of the week holding particular religious significance. The 28-day month, or a complete cycle of the Moon, is a bit too large a period of time to manage effectively, and so the Babylonians divided their months into four equal parts of seven.
The number seven is not especially well-suited to coincide with the solar year, or even the months, so it did create a few inconsistencies.
However, the Babylonians were such a dominant culture in the Near East, especially in the sixth and seventh centuries B.C., that this, and many of their other notions of time – such as a 60-minute hour – persisted.
The seven-day week spread throughout the Near East. It was adopted by the Jews, who had been captives of the Babylonians at the height of that civilization’s power. Other cultures in the surrounding areas got on board with the seven-day week, including the Persian empire and the Greeks.
Centuries later, when Alexander the Great began to spread Greek culture throughout the Near East as far as India, the concept of the seven-day week spread as well. Scholars think that perhaps India later introduced the seven-day week to China.
Finally, once the Romans began to conquer the territory influenced by Alexander the Great, they too eventually shifted to the seven-day week. It was Emperor Constantine who decreed that the seven-day week was the official Roman week and made Sunday a public holiday in A.D. 321.
The weekend was not adopted until modern times in the 20th century. Although there have been some recent attempts to change the seven-day week, it has been around for so long that it seems like it is here to stay.
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This article has been updated to correct the details on Earth’s revolution around the Sun.
The unicorn is an enduring image in contemporary society: a symbol of cuteness, magic, and children’s birthday parties.
But while you might dismiss this one-horned creature as just a product for Instagram celebrities and five-year-old girls, we can trace the lineage of the unicorn from the 4th century BCE. It evolved from a bloodthirsty monster, to a tranquil animal bringing peace and serenity (which can only be captured by virgins), to a symbol of God and Christ.
These days the term unicorn can refer to a privately held start-up company valued at over US$1 billion,
a single female interested in meeting other couples, or the characters in My Little Pony.
Over the centuries, the meaning and imagery of the unicorn has shifted and persisted. But how did we get here?
Ferocious beasts and where to create them
The earliest written account of the unicorn comes from the text Indica (398 BCE), by Greek physician Ctesias, where he described beasts in India as large as horses with one horn on the forehead.
Ctesias was most likely describing the Indian Rhinoceros. The unicorn horn, he wrote, was a panacea for those who drink from it regularly.
In the first-century CE, claiming to quote Ctesias, the Roman naturalist Pliny (Natural History, 77 CE), wrote that the unicorn was the fiercest animal in India, with the body of a horse, the head of a stag, the feet of an elephant, the tail of a boar, and a single horn projecting from the forehead.
Pliny also embellished the animal’s description by adding a trait that became extremely significant to society in the Middle Ages: it was impossible to capture the animal alive.
Just over a century later, the second-century CE Roman scholar Aelian compiled a book about animals based on Pliny. In his On the Nature of Animals, Aelian wrote that the unicorn grows gentle towards the chosen female during mating season.
The unicorn’s tender disposition when near the female became a highly symbolic trait for authors and artists of the Middle Ages, who believed it could only be captured by a virgin.
Despite the authoritative texts of the Greeks and Romans, the unicorn remained mostly unknown in the centuries leading up to the Middle Ages. For the public to become familiar with it, the creature had to come out of the library and develop a role in everyday events and popular culture: ie a role in Christianity.
Lost in translation
It was in the third-century BCE that the unicorn entered religious texts – although only by accident.
Between 300 and 200 BCE, a group of 70 scholars gathered together to create the first translation of the Hebrew Old Testament in Koine Greek. Although the Hebrew term for unicorn is Had-Keren (one horn), in the text commonly known as Septuagint (seventy) the scholars made an error when translating the Hebrew term Re’_em (ox), from Psalms as monokeros. In effect, they changed the word “ox” to “unicorn.”
The unicorn’s inclusion in a text of such magnitude laid the foundation for an obsession with the creature that thrived in both literary and visual arts from the earliest dates of the Middle Ages and continues to the modern day.
By the 12th century, the one-horned animal came to be associated with the allegory provided in the Physiologus, a collection of moralised beast tales on which many medieval bestiaries are based. One of the most widely read books in the Middle Ages, the Physiologus often identifies Christ with the unicorn.
The illustrations that accompany textual references to the unicorn in the Bible and medieval bestiaries often showed the allegorical representation rather than the literal.
So instead of images depicting Christ as a man, the artists drew horses and goats with one large horn protruding from its head. In this medieval legend, the fanciful myth of the one-horned animal became the foundation of the unicorn image that circulated throughout Europe.
Contemporary images of the unicorn have changed very little since the medieval era. The creature in The Lady and the Unicorn tapestries in the Cluny museum in Paris, symbolising various overlapping meanings including chastity and heraldic animals, looks a lot like the My Little Pony characters Rarity and Princess Celestia.
Imagery of the unicorn persisted sporadically in literature, film and television through the 20th century, but the 2010s saw interest boom.
The modern Instagram star
Social media helped lure the magical creature into quotidian life – the one-horned horse looks great as a Facebook emoji and surrounded by rainbows on Instagram. National Unicorn Day (April 9) was first observed in 2015.
Searches for “unicorns” reached an all-time high in April 2017, the same month Starbucks introduced the colour and taste-changing Unicorn Frappuccino, sparking a trend in adding glitter and rainbow colours to any food or beverage.
Now, the unicorn is marketed to children and adults alike on coffee mugs, keychains, stuffed animals, t-shirts. In secular contemporary culture it has become an LGBTI+ icon: a symbol of hope, something “uncatchable.”
The contemporary unicorn is a far cry from Ctesias’ beasts. Social media platforms like Instagram encourage us to project an idealised version of our life: the unicorn is a perfect symbol for this ideal.
If the last decade is anything to go by, its intrigue will only continue to grow.