The Temple at Uppsala was a religious center in the ancient Norse religion once located at what is now Gamla Uppsala (Swedish "Old Uppsala"), Sweden attested in Adam of Bremen's 11th-century work Gesta Hammaburgensis ecclesiae pontificum and in Heimskringla, written by Snorri Sturluson in the 13th century. Theories have been proposed about the implications of the descriptions of the temple and the findings (or lack thereof) of the archaeological excavations in the area, along with recent findings of extensive wooden structures and log lines that may have played a supporting role to activities at the site, including ritual sacrifice.
In Gesta Hammaburgensis ecclesiae pontificum, Adam of Bremen provides a description of the temple. Adam records that a "very famous temple called Ubsola" exists in a town close to Sigtuna. Adam details that the temple is "adorned with gold" and that the people there worship statues of three specific gods that sit on a triple throne. Thor, whom Adam refers to as "the mightiest," sits in the central throne, while Wodan (Odin) and Fricco (Freyr) are seated on the thrones to the sides of him. Adam provides information about the characteristics of the three gods, including that Fricco is depicted with an immense erect penis, Wodan in armor ("as our people depict Mars," Adam notes) and that Thor has a mace, a detail which Adam compares to that of the Roman god Jupiter. Adam adds that, in addition, "they also worship gods who were once men, whom they reckon to be immortal because of their heroic acts [...]."
Adam says that the three gods have a priest appointed to them each who offer up sacrifices to the deities from the people. If famine or plague occurs, a sacrifice is made to Thor; if there is war, a sacrifice is made to Wodan; if a marriage is to be held, a sacrifice is made to Fricco. Adam continues that "every nine years there is a communal festival of every province in Sweden held in Ubsola; and those already converted to Christianity have to buy themselves off from the ceremonies."
Adam details sacrificial practices held at the temple; Adam describes that nine males of "every living creature" are offered up for sacrifice, and tradition dictates that their blood placates the gods. The corpses of the nine males are hung within the grove beside the temple. Adam says that the grove is considered extremely sacred to the heathens, so much so that each singular tree "is considered to be divine," due to the death of those sacrificed or their rotting corpses hanging there, and that dogs and horses hang within the grove among the corpses of men. Adam reveals that "one Christian" informed him that he had seen seventy-two cadavers of differing species hanging within the grove. Adam expresses disgust at the songs they sing during these sacrificial rites, quipping that the songs are "so many and disgusting that it is best to pass over them in silence."
Adam describes that near the temple stands a massive tree with far-spreading branches, which is evergreen both in summer and winter. At the tree is also a spring where sacrifices are also held. According to Adam, a custom exists where a man, alive, is thrown into the spring, and if he fails to return to the surface, "the wish of the people will be fulfilled."
Adam writes that a golden chain surrounds the temple that hangs from the gables of the building. The chain is very visible to those approaching the temple from a distance due to the landscape where the temple was built; it is surrounded by hills, "like an amphitheatre." The feasts and sacrifices continue for a total of nine days, and during the course of each day a man is sacrificed along with two animals. Therefore, in a total of nine days twenty-seven sacrifices occur, and, Adam notes, these sacrifices occur "about the time of the spring equinox."
Rudolf Simek says that, regarding Adam of Bremen's account of the temple, "Adam's sources for this information are of extremely varying reliability, but the existence of a temple at Uppsala is undisputed." Simek says that details of Adam's accounts have been cited as potentially influenced by the description of Solomon's Temple in the Old Testament. Simek notes, at the same time, similar chains as described by Adam appear on some European churches dating from the 8th to 9th centuries, although the description of the temple chain having been made of gold may be an exaggeration. Simek says that the numerous attempts at reconstructing the temple based on the postholes may overestimate the size of the temple, and that notes that "more recent" research indicates that the site of the 11th-century temple probably adjoined the choir of the church standing there today, while the postholes discovered by Lindqvist may instead point to an earlier, burnt-down temple at the same site.
Orchard (1997) states that "it is unclear to what extent Adam's description has a basis in historical fact rather than lurid fiction" yet that Adam's account contains "a good deal of useful information (as well as considerable speculation)." Orchard points out that Adam's description of the temple has often been questioned "on several levels" and that Thietmar of Merseburg produced a considerably less detailed but similar account of sacrifices held in Lejre, Denmark earlier in the 11th century.
In the Ynglinga saga compiled in Heimskringla, Snorri presents a euhemerized origin of the Norse gods and rulers descending from them. In chapter 5, Snorri asserts that the æsir settled in what is now Sweden and built various temples. Snorri writes that "Odin took up his residence at the Maelare lake, at the place now called Old Sigtun. There he erected a large temple, where there were sacrifices according to the customs of the Asaland people. He appropriated to himself the whole of that district, and called it Sigtun. To the temple priests he gave also domains. Njörðr dwelt in Nóatún, Frey in Upsal, Heimdal in the Himinbergs, Thor in Thrudvang, Balder in Breidablik; to all of them he gave good estates."
In chapter 10, after Njörðr has died, his son Freyr comes to power and "he was called the king of Swedes and received tribute from them." Freyr's subjects loved him greatly, and he was "blessed by good seasons like his father." According to the saga, Freyr "erected a great temple at Uppsala and made his chief residence there, directing it to all tribute due to him, both lands and chattels. This was the origin of the Uppsala crown goods, which have been kept up ever since."
In 1926, Sune Lindqvist conducted archaeological investigations in Gamla Uppsala and discovered postholes beneath the church in Gamla Uppsala. These postholes may be lined up with the result of concentric rectangles, and subsequently various attempts at reconstructions of the temple have been attempted based on this discovery.
Price and Alkarp (2005) have been among those who dispute the 1926 interpretation:
Though still maintained today in school textbooks and elsewhere, this conclusion is clearly erroneous as the postholes can be shown stratigraphically to belong to several different phases of construction.
Using ground penetrating radar and other geophysical methods, Price and Alkarp found the remains of what they interpreted as a wooden construction located directly under the northern transept of the medieval cathedral, and two other buildings, one of them a Bronze Age building, and the other possibly a Viking Age feasting hall. Orchard (1997) says that archaeological digs in the area "have failed to reveal anything on the scale proposed for the temple" yet that three burial mounds at the location reveal the importance of the site.
In 2013, the remains of two lines of large wooden poles were discovered. One line is approximately a kilometer long and the other half a kilometer with each pole being separated by 5–6 meters. The poles have been estimated to be 7 meters in length.