Name and place Unni died on 17 September 936, though it is unclear if Adam's assertion of him and King Ring being contemporaries is the author's guesswork. King Ring is not mentioned in the Norse king lists and sagas, such as Hervarar saga ok Heiðreks. The name is however borne by the Swedish ruler who was victorious in the legendary Battle of Bråvalla, Sigurd Ring. It is not otherwise attested among the members of the Viking Age royal family. It has sometimes been speculated that his true name was Olof (Anlaufr), represented in Latin chronicles as Anulo, which could have been misinterpreted as Latin annulus, meaning "ring". There has also been some speculation about the location of Birka where Unni died. A runic inscription on a cross at the church of Sund in Åland has been interpreted by local scholars as Wini (Unni), which would call for a radical reinterpretation of the historical geography of Viking Age Sweden. The dominating view among historians and archaeologists is nevertheless that Birka was situated on Björkö in Lake Mälaren. The German encroachment on Scandinavia, which resulted in Unni's visit, may also have alerted the rulers of Birka. The family of Danish rulers who were defeated in 934 is said to have come from Sweden, although this statement has been much-disputed by modern scholars. At any rate Birka apparently had strong commercial relations with Hedeby. The fortifications of Birka were strengthened around 940 as the gravel walls were heightened, and palisades seem to have been erected. See also Early Swedish History References Semi-legendary kings of Sweden 10th-century Swedish monarchs