The Gods Behind the Days of the Week

It is of common knowledge that the days of the week are so named after gods and goddesses. But how and why did that happen? Why were such names chosen and what each of them tells us about the deities?

Well... first of all, let's start at the beginning. The concept of week itself probably developed in ancient Babylon in the region of mesopotamia (nowadays Iraq and parts of Syria), where a month was divided into more or less four seven-day periods to match the four phases of the moon. This didn't exactly work out as some weeks were longer than others but by the time of ancient Greece, the seven-day cycle was firmly established and each day of the week had a common name.

To the greeks, the days of the week were so named:

Monday: "hemera selenes" - meaning “day of the moon”
Tuesday: "hemera Areo"- meaning “day of Ares” (the Greek God of War)
Wednesday: "hemera Hermu" -  “day of Hermes” (the Greek God of commerce and travel)
Thursday: "hemera Dios" -  “day of Zeus” (supreme Greek God of the heavens, commonly known as the god of thunders)
Friday: "hemera Aphrodites" - “day of Aphrodite” (Greek Goddess of love and beauty)
Saturday: "hemera Khronu" - “day of Cronus” (supreme Greek God of the universe before Zeus)
Sunday: "hemera heliou" - “day of the sun”

The romans, on the other hand, used the roman equivalent of the greek gods:

Monday: "dies lunae" - “day of the moon”
Tuesday: "dies Martis" - “day of Mars” (the Roman God of War)
Wednesday: "dies Mercurii" - “day of Mercury” (the Roman God of commerce and travel)
Thursday: "dies Jovis" - “day of Jupiter” (supreme Roman God of the heavens)
Friday: "dies Veneris" - “day of Venus” (Roman Goddess of love and beauty)
Saturday: "dies Saturni" - “day of Saturn” (Roman God believed to have ruled in an earlier age)
Sunday: "dies solis" - “day of the sun”

The Welsh for instance, follow the Latin pattern entirely, as do many of the Romance languages throughout Europe. However, the English case is different; it doesn’t follow either Latin or Greek names. Instead, it follows the day names first given by the Anglo-Saxons, and these appear completely different from those of Greek or Latin deities.

Monday: "Mōnandæg" - “day of the moon”
Tuesday: "Tīwesdæg" - “day of Tiw” (the Anglo-Saxon God of war)
Wednesday: "Wōdnesdæg" - “day of Woden” (the chief Anglo-Saxon God equivalent to the Scandinavian Odin)
Thursday: "Þunresdæg" - “day of Thunor/Donar” (the Anglo-Saxon God of thunder, represented as riding a chariot, the equivalent of the Scandinavian Thor). Strictly, the day means “day of Thunder” after Thunor.
Friday: "dies Frīgedæg" - “day of Freya/Freyja or Frigg” (the Anglo-Saxon Goddesses of love and beauty)
Saturday: "Sæternesdæg" - “day of Saturn” (no equivalent Anglo-Saxon God so the Roman God is reused in this case)
Sunday: "Sunnandæg" - “day of the sun” (dæg is pronounced “day” and Sunna/Sol is the goddess of the sun)

It appears that the attributes of each deity are identical (except for Wednesday and Thursday). The Anglo-Saxons clearly did not invent their own terms for each day of the week, but followed Roman practice, turning the Roman deity names into their own. It also tells us how Anglo-Saxons thought about their Gods and which they most closely linked with the Roman equivalent. However, the early Anglo-Saxons saw Thunor (in ancient Norse -Thor) as having qualities shared by Mercury, which indicates that firstly Thor had different attributes to the Norse/Germanic peoples, and wasn't yet the god of Thunder and giant slayer. It is possible that Thor used his chariot for commerce and not just riding to battle. In much of the Western world, the day names are very similar, either taken directly from Latin, or, as we have seen with the English case, taken from the equivalent of the Anglo-Saxon deities.