In 1164 the "archbishopric of Sweden" was established at "Gamla Uppsala", once the political centre of the "Svear kingdom" in the late Iron Age and a stronghold of pre-Christian cult. This highly symbolic decision was manifested through the construction of one of the largest churches in Scandinavia.
The cathedral church at Gamla Uppsala was allegedly built on the same spot as the famous "pagan temple2 described by "Adam of Bremen" in the early 1070s. Excavations carried out there in 1926 revealed a highly complex stratigraphic sequence and a confusing set of postholes that were immediately interpreted as the remains of the temple. Though still maintained today in school textbooks and elsewhere, this conclusion is clearly erroneous as the postholes can be shown stratigraphically to belong to different phases of construction.
The exact events of the period c. 1050-1150 in Gamla Uppsala have never been satisfactorily understood, but there is clear evidence to suggest that the cathedral was by no means the first church to have been built on the site. In an effort to elucidate this early history of the church plateau, in 2003-04 the authors examined the area with ground-penetrating radar. In this paper we discuss some of the more important results of these investigations.