The Temple of Uppsala
Around the year 1070, Adam of Bremen described the great pagan cult center of Uppsala, Sweden in his work Gesta Hammaburgensis ecclesiae pontificum, the most famous source to pagan ritual practice in Sweden. It was written with the agenda of showing how barbaric and immoral were the practices and religion of the pagans, in defense of the still somewhat fragile position of the Christian church in Sweden at the time. Thus it cannot be read as an objective source to paganism, but rather as a strongly biased attack on paganism. Yet it is one of the only sources we have, and must make do with. The temple of Uppsala is described in the fourth book, chapter 26:
“This people have a widely renowned sanctuary called Uppsala. By this temple is a very large tree with extending branches. It is always green, both in winter and in summer. No one knows what kind of tree this is. There is also a spring there, where the heathens usually perform their sacrificial rites. They throw a live human being into the spring. If he does not resurface, the wishes of the people will come true.
The Temple is girdled by a chain of gold that hangs above the roof of the building and shines from afar, so that people may see it from a distance when they approach there. The sanctuary itself is situated on a plain, surrounded by mountains, so that the form a theater.
It is not far from the town of Sigtuna. This sanctuary is completely covered with golden ornaments. There, people worship the carved idols of three gods: Thor, the most powerful of them, has his throne in the middle of the hall, on either side of him, Odin and Freyr have their seats. They have these functions: “Thor,” they say, “rules the air, he rules thunder and lightning, wind and rain, good weather and harvests. The other, Odin, he who rages, he rules the war and give courage to people in their battle against enemies. The third is Freyr, he offers to mortals lust and peace and happiness.” And his image they make with a very large phallus. Odin they present armed, the way we usually present Mars, while Thor with the scepter seems to resemble Jupiter. As gods they also worship some that have earlier been human. They give them immortality for the sake of their great deeds, as we may read in Vita sancti Ansgarii that they did with King Eirik.”
The following is largely quoted, or abridged from the book Frey’s Offspring: Rulers and Religion in Ancient Svea Society by Olaf Sundqvist (2002) p. 94-136. Most of the evidence and copious examples have been truncated or omitted. Please refer to the original text for details:
“Gamla Uppsala is one of the most complex archaeological monuments in Scandinavia. The finds are sufficient for it to be considered a central place during the entire Late Iron Age. The mounds, boat-graves, traces of hall(s) and the wall to the north indicate the presence of a ruling stratum at least from the 5th or the 6th century. These finds, together with the phosphate values at the Eastern Mound and the Middle Mound, may also indicate ritual activity. Archeological analysis shows the site has been settled since the Roman period. It is an important site from at least the Migration Period up to the Middle Ages, though it may have experienced some troughs during the 9th century, after the hall on the southern plateau was burnt down.” SOURCE