What do names for days of the week signify? In Germany, there is a very simple interpretation. Dienstag (Tuesday), as many responsible Germans believe, comes from dienst (duty), while Freitag (Friday), at the end of the working week, is the day when one is free (frei).
Both explanations are wrong. In fact, the German names for days of the week actually go back to before Charlemagne, King of the Franks and then emporer of the Holy Roman Empire between 800 and 814. The Teutonic deities were aligned with their Roman counter-parts across the week.
Thus the Roman god of war, Mars, became his Germanic colleague, Diu. Mardi in French, but Dienstag in German which became Tuesday (from Tiu) in English.
Venus, the goddess of love, had to make way for her Teutonic incarnation, Freya. These days French lovers start their weekend on vendredi, the Germans on Freitag and the English on Friday.
But Charlemagne's mission to civilise the heathens of the North and teach them Christianity led him to remove Woden, the father of the Teuton gods, from his position in the middle of the week.
He is still there in Nordic languages and English (Woden's day) but sacrificed in the German language for a more practical solution. Mittwoch - middle of the week, the only day of the week that means what it says.