Świętosława
Świętosława is the name some historians have assigned a Polish princess, the daughter of Mieszko I of Poland and sister of Bolesław I of Poland, who married two Scandinavian kings. According to German chroniclers, this princess, whose name is not given, was married first to Eric the Victorious of Sweden and then to Sweyn Forkbeard of Denmark, giving the former a son, Olof, and the latter two sons, Harald and Cnut. Because a documented sister of Cnut seems to have borne the Polish name Świętosława, it has been speculated that this may also have been the name of their  mother, the Polish princess of the chroniclers. The Icelandic sagas give her role as successive queen of these two monarchs to 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, 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, while he sees Sigrid the Haughty as an authentic subsequent wife of Sweyn as widow of Eric the Victorious, being mother of Eric's son, Olaf, and of Sweyn's daughter, Estrid. He further suggests although Świętosława was not the name of Sweyn's Polish wife, the name had a  history in the family, that perhaps it was the name of the otherwise unknown wife of Mieszko's father, Siemomysł. Contemporary sources. There is scant material in medieval chronicles to provide details regarding the marriages of Sweyn of Denmark and Eric of Sweden: