In the 13th century collection of sagas, Heimskringla, Snorri Sturluson tells that Sweyn Forkbeard was captured in an attack on the Jomsvikings, and turned over to Burislav, king of Wendland.
Swein had sent his sister Tyri to marry the Wendish king Burislav, who had been father of Swein's first wife, Gunhild.
In order to win Astrid, the daughter of the Wendish chieftain Burislav, he promised to liberate the Wends of the tribute they had to pay to the Danes.
Burislav |