The Icelandic sagas identify the queen of these two monarchs in turn as Sigrid the Haughty, daughter of Skagul Toste.
This account is considered less reliable than the contemporary chroniclers by a number of scholars, according to Birgitta Fritz in Svenskt biografiskt lexikon,[1] and the historical authenticity of Sigrid is viewed skeptically.
Snorre Sturlasson also mentions a Slavic princess he calls Gunhild of Wenden, daughter of king Burislav of the Wends, the ancient Slavs inhabiting the northern regions of modern Poland, and it has been suggested that Gunhild may be a somewhat confused account of the sister of the Polish king Bolesław I described by the chroniclers.
Polish genealogist Rafał Prinke sees the German chroniclers as having combined the roles of two distinct wives of Sweyn Forkbeard, with the Polish princess actually being Gunhild, mother of Cnut, Harold and a daughter Świętosława.
[2] There is scant material in medieval chronicles to provide details regarding the marriages of Sweyn of Denmark and Eric of Sweden: