A shieldmaiden was a woman who had chosen to fight as a warrior in Scandinavian folklore and mythology. They are often mentioned in sagas such as Hervarar saga and in Gesta Danorum. Shieldmaidens also appear in stories of other Germanic nations: Goths, Cimbri, and Marcomanni. The mythical Valkyries may have been based on the shieldmaidens. There are few historical attestations that Viking Age women took part in warfare, but the Byzantine historian Johannes Skylitzes records that women fought in battle when Sviatoslav I of Kiev attacked the Byzantines in Bulgaria in 971. When the Varangians had suffered a devastating defeat, the victors were stunned at discovering armed women among the fallen warriors. When Leif Ericson's pregnant half-sister Freydís Eiríksdóttir was in America, she is reported to have taken up a sword, and, bare-breasted, scared away the attacking Native Americans. The fight is recounted in the Greenland saga, though Freydís is not explicitly referred to as a shieldmaiden in the text.