least have been connected to, Viking expansion, with petty kings increasing their power through aggressive military ventures directed both to foreign lands (i.e. Viking raids) and against their neighbors. In his 12th-century work Gesta Danorum, Danish author Saxo Grammaticus wrote that the Swedish kings of the Viking Age were part of the dynasty of the Ynglings, a possibly entirely invented line of ancient Scandinavian kings supposedly descended from Odin, but this does not accord with the Icelandic sagas, which hold that the Ynglings were driven from Sweden in the middle of the 7th century and replaced by other dynasties. There is no preserved contemporary name for the Viking Age dynasty, and there exists no universally accepted name for them in modern historiography. The name "House of Munsö" () derives from a questionable and speculative theory that the kings of the 9th century transferred their royal seat of power from Uppsala (an important early political center in Sweden) to the island of Munsö in the lake Mälaren. The supportive evidence for this theory; a large burial mound on Munsö and a contemporary account by German missionary Rimbert giving the impression that the Swedish king had his seat near the island-settlement of Birka, is quite thin. Since the name "House of Munsö" arguably takes a stand in favor of this theory, it is commonly avoided in modern Swedish scholarship. The name "House of Uppsala" () derives from the fact that the Icelandic sagas often designate legendary Swedish rulers as kings "in Uppsala", and is similarly problematic. The dynasty is thus sometimes simply designated as "the Old dynasty" (), a more neutral designation. The rarely used name "House of Björn Ironside" () comes from the dynasty supposedly descending from the legendary Viking Björn Ironside according to the later Icelandic sagas. The big burial mound at Munsö was attributed, without evidence, to Björn Ironside by 18th-century historians, an identification that is not accepted by historians today. Kings of the Munsö dynasty The line of Munsö dynasty kings presented by the Icelandic sagas is not accepted by modern historians, the legendary kings (including the supposed founder of the dynasty, Björn Ironside) typically not being recognized as actual historical figures. The four kings of the dynasty whose existence is corroborated by multiple sources, and who are thus generally accepted as real historical kings of Sweden and recognized as such by the modern Swedish monarchy are Eric