Origins: Days of the Week

Have you ever wondered why the days of the week are named as they are?

If so, today’s blog post is for you, as we’re taking a peek at the history of the days of the week.

The days of the week as we now know them were originally named after the sun, moon and five planets of our solar system:

February CalendarSunday — Sun’s day (“day of the Sun”)
Monday — Moon’s day (“day of the Moon”)
Tuesday — Tiu’s day (“day of Mars”)
Wednesday — Woden’s day (“day of Mercury”)
Thursday — Thor’s day (“day of Jupiter”)
Friday — Freya’s day (“day of Venus”)
Saturday — Saturn’s day (“day of Saturn”)

Firstly, the Ancient Greeks named days week after the sun, the moon and the five planets known as Ares, Hermes, Zeus, Aphrodite and Cronus – so named after their gods.

The Romans then named the days after their five gods which were Mars, Mercury, Jove (Jupiter), Venus and Saturn.

The Germanic peoples (including our ancestors, the Anglo-Saxons) next substituted their own similar gods which became Tiu, Woden, Thor, Freya but Saturn remained.

Finally, the names of the days of the week then passed into the languages of southern and western Europe, as they developed.

Around the first century, Saturday was seen as the first day of the week but as the sun became more important in early Roman worship, Sunday became the first day of the week and Saturday was made the seventh.

The seven-day week is used by the majority of the world and has become the international standard as specified by the International Organization for Standardization (ISO 8601). This standard keeps everything clear so that everyone uses the same methods of telling the date and time!


As recently as 1929, the USSR adopted a five day week, and subsequently a six day week. Whilst the names of the days remained the same, work schedules were rotated in 5 and then 6 day periods. The USSR re-adopted the seven day week in 1940.

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