Januari is a month when many Heathens pay extra tribute to Thor. In pre-Christian Northern Europe, mid-january would be the traditional time for Yule and blóts were often held in honour of the Deities of the season, among which is Thor. The Yuletide often ended with a feast and a blót to Him. And since this is the season of honoring Thor, I’d like to pay extra attention to the Thunderer and write more about Him.
Today, I wanted to write about the beginnings of the worship of Thor. It’s hard to pinpoint an exact time but there is evidence that the Proto-Indo-Europeans worshipped a Thunder God who was depicted as wielding either a hammer or an axe. Different cultures and languages evolved from the PIE group and different Names and imagery were attributed to Him. It is not unlikely that Thor and a God like the axe-wielding Slavic Perun have the same origin.
When it comes to Scandinavia specifically there is hints that the Thunderer was worshipped already back in the Bronze Age and this 3000 year old petroglyph is believe to be the oldest known depiction of Thor:

This petroglyph found in Tanum, Sweden, is interesting for a number of reasons. Firstly, the figure rides in a chariot pulled by what could be a goat and Thor rides a chariot drawn by two goats. Secondly, the figure seems to be wielding something that could be a hammer or an axe. And thirdly, the figure sports an erection, a sign of being a bringer of fertility. It also looks like a thunder bolt could be shooting out of the penis. Later depictions of the Thunderer rarely involve erections, but Thor is very much a fertility Deity who is often called on to bring fertility to humans, animals and crops.
So, the worship of Thor in Scandinavia could be as old as 3000 years!