Sverresborg Well Man genomic sequencing. Corroborating written history with ancient DNA: the case of the Well-man described in an Old Norse saga

Analyses of DNA from ancient remains found in an archaeological context have proven a valuable independent source of information about human history. Here, we use this approach to shed light on human remains found in an ancient well at the ruins of Sverresborg castle in Trondheim, Norway. Intriguingly, a passage in Sverris Saga, the Old Norse saga of King Sverre Sigurdsson (1177–1202 CE), describes a successful raid of Sverre’s castle (1197 CE), where the victors end by throwing a man into the castle’s drinking well. This circumstantial evidence and a 14C date of 1190–1285 CE, make it very likely that the remains belong to the Well-man in Sverris Saga. We sequenced the Well-man’s genome to a depth of 3.4X and compared it to an extensive set of genotypes from present-day populations in Scandinavia and the rest of Europe. Our results show that he was most closely related to the present-day inhabitants of the southernmost counties of Norway (Vest and Aust-Agder). This was surprising, as King Sverre’s defeated army was from the north of Norway, whereas the raiders were from the south. Our results further show that the distinctive pattern of genetic drift that characterises present-day Norwegians from the Agder counties was already in place 800 years ago.