Where do English Weekday names come from?

Let’s take a look at the seven days of the week and how they came to be named.

The first day of the week was named after the sun – dies Solis – day of the sun in Latin and later Sunnon-dagaz in old Germanic. It’s easy to see where the English word Sunday comes from here.
It’s similarly easy to see where this weekday name originates too. Monday is the moon day – dies Lunae in Latin, becoming Mon(an)dæg in Old English.
Whereas most English days of the week retain their associations with the Roman gods, some were substituted for the names of the equivalent Germanic gods, because English is a Germanic language.
Tuesday was named for the Roman god of war, Mars, so in Latin was known as dies Martis. However, the Germanic god of war was known as Tiu and the English day of the week is derived from this Germanic god’s name instead, first known as Tiwsday and eventually Tuesday.
Similarly, the Germanic equivalent of the Roman god Mercury was the equally as swift Woden. And so this day, which started out in Latin as dies Mercurii became Woden’s day in old Germanic, eventually becoming Wednesday in English.
Jupiter, also known as Jove, is the supreme Roman god and patron of the Roman state. He is the god that created thunder and lightning. Thor is the Norse god of thunder, often shown riding through the sky in a chariot. And it’s from this Norse god that we see the Latin dies Jovis (day of Jupiter) become Thor’s day and eventually Thursday.
Venus is the Roman goddess of love and beauty, and in Latin her day was known as dies Veneris. We get the English name for Venus’ day from Frigg, the Norse goddess of love and the heavens, and possibly Fria, the Teutonic goddess of love and beauty. In Germanic we have Frije-dagaz, later becoming Friday in English.
We end with an easy one. Saturn is the Roman god of agriculture, known in Ancient Greece as Cronos. In Latin we have dies Saturni and it’s not hard to see that Saturday today is still very much Saturn’s day.