The Origin of the Names of the Days of the Week

When is the First Day of the Week?

Today, many people consider Monday as the first day of the week, and Sunday the last day. However, many times the first day of the week in the calendar is Sunday, and the last day Saturday. Because of this disagreement, people often get confused about the first day of the week. Is it Sunday or Monday?

This is important in understanding the bible. According to the bible, the day of rest or the Sabbath is the 7th day of the week? Is the 7th day Saturday or Sunday? Or even another day?

Ancient Diagram showingh the days and week

The First Day of the Week in the Roman Calendar

Since the calendar we use today originated from the Roman Calendar, more specifically the Gregorian Calendar, we can get the idea of when the first day of the week from the ancient Roman calendar. The Roman calendar was based on the Babylonian calendar, which divided the week into seven days and assigned each day with their own gods named after the planets around the earth.

The Babylonians considered the Sun and the Moon the most important planets(?) and the first day was Sunday and the second day Monday. This practice was adopted by the Greeks and Romans, and later by Anglo-Saxon, which we use as the names for the days of the week today. The only difference was that each kingdoms changed the names of the week to suit the names of their own gods.

If you look at the table below, you can easily know how the names of the week changed throughout the history.


1st Day

2nd Day

3rd Day

4th Day

5th Day

6th Day

7th Day


Sun (4th planet from the earth)

Moon (1st planet from the earth)

5th planet from the earth

2nd planet from the earth

6th planet from the earth

3rd planet from the earth

7th planet from the earth




















Tiw (The god of war)

Wodan (The god of wisdom)

Thor (The god of thunder)

Frigg (The goddess of beauty)










Monday as the First Day of the Week

Through the history of the change of the names, we can see that the first day of the week was always Sunday, not Monday, and the last and 7th day of the week was Saturday, not Sunday. Then when did the custom of considering Monday as the first day of the week start?

As the time goes by, the world has become more and more smaller due to the technological development in the communication and transportation. Industrialization and globalization made it necessary to standardize the time and dates more strictly to synchronize the work schedule throughout the world.

For this reason, the International Standardization Organization or ISO unified the concept of measuring the time and date. Today according to ISO, the days of the week is stated as “the weekday number, from 1 through 7, beginning with Monday and ending with Sunday”.

The message in this statement is quite clear that the week is made up of 7 days and the first day is Monday and the last day Sunday. This kind of the concept of the week days was first regulated in ISO around 1988 and later it was more updated.

Jewish Calendar


Through this we can understand the convention of the Sunday as the last and 7th day of the week started quite recently. Originally, Sunday was the first day of the week and Saturday the last and 7th day of the week. Therefore, it is quite natural to say that the first day in the bible is Sunday and the last and 7th day Saturday. The biblical Sabbath is Saturday, not Sunday.

Leave a Reply

Your email address will not be published.