AARHUS, DENMARK—According to a statement released by Aarhus University, artifacts unearthed at the market town of Ribe in southwest Jutland have been precisely dated in order to trace the development of Viking trade networks with Norway, Western Europe, and the Middle East. The new technique employs solar particle events, which cause a spike in atmospheric radiocarbon, to create a calibration curve and reduce the uncertainty in radiocarbon dating. Such spikes are identified in tree rings and archaeological sequences, explained team leader Bente Philippsen. The researchers were able to identify a spike in atmospheric radiocarbon in a layer at Ribe and dated it to A.D. 775, which allowed them to anchor another 140 radiocarbon dates at the site. Thus, goods imported from Norway have been dated to A.D. 750, said researcher Søren Sindbæk, and the arrival of large numbers of beads from the Islamic empire in the Middle East has been dated to A.D. 790, with a margin of error of just ten years. The beads signal the expansion of trade networks and the beginning of the Viking Age, he explained. To read about another recent discovery from Ribe, go to "Viking Roles."