How exhausting would a longer week be, or how fast would the week feel if it was shorter? Why does it feel like the seven day week was appropriate?
Let’s explore the genesis of the 7 day week concept and why it became universally upheld.
Long before indoor plumbing, the Babylonians were already studying the heavens, monitoring and interpreting movement of the planets, stars, moon and the sun. Babylon was located in today’s country of Iraq, and was home to scholars of the cosmos, who are historically credited for the seven-day week.
Babylonians were such a dominant culture in the Near East, and especially in the sixth and seventh centuries B.C., that they influenced their neighbours and trade partners to adopt the seven-day week. They are also responsible for many other notions of time such as a 60-minute hour. But that’s a story for another day.
The spread was mostly due to the dominance of the Babylonians through conquests and trade, first to their subjects, then to their neighboring empires like the Persians and the Greeks. Later, it spread widely further East courtesy of Alexander the Great. The renowned Greek conquerer dominated the Mesopotamian region, North Africa regions such as Egypt and even the East as far as India. The spread of the Greek culture which had already adopted the seven-day week culture cemented the Babylonian time structure. It’s believed that because of India’s adoption of the concept, it spread it further East to China and it’s neighbours.
The week names are from seven celestial objects they studied
Because the number seven is not especially well-suited to coincide with the solar year, or even the months, it did create a few inconsistencies.
For example, the number seven by itself is not perfectly divisible into the three hundred and sixty Five days in a calendar year, even for a leap year, which means that the quarter day we save up after four years don’t change the seven days week.
The Babylonians divided their lunar months into seven-day weeks, with the final day of the week holding particular religious significance. With a 28-day month cycle of the Moon, a bit too large a period of time to manage effectively, the Babylonians then divided their months into four equal parts of seven, which they called Weeks.
The Monday to Sunday weekdays as we know them are a representation of the naming planets, ordered from the slowest to the fastest moving planets together with the sun and the moon. This is called the Charldean order.
The Charldean order places Apollo (Sunday) – the day of the sun – as the first day of the week, followed by Diana (Monday) – the day of the moon. Mars is Tuesday, Mercury is Wednesday, Jupiter is Thursday, Venus is Friday and the last day of the week is Saturn which is represented as Saturday.
Finally the seven day week was made eternal through a decree in AD 321 by King Constantine who then made the last day of the week which is Sunday be an official public holiday. That’s why Christian based communities have Sunday as their testing day, unlike Islamic ones which do the same on Friday.
And that’s why today, the whole world uses the Babylonian calendar system.