Slavic piracy

The robbery committed by Slavic tribes on the Baltic Sea and its coast during the Middle Ages was initially a part of the Viking movement. We know about Slavic warriors in the 10th century from Scandinavian poetry. This time, the center of the Slavic warriors was Wolin known later as Jomsborg. It was finally destroyed by the King Magnus the Good in 1042. It was possibly the origin of the legend of the city of Vineta. In the 12th century, there was intensification of Slavic piracy. It was connected with German and Polish expansion which pushed the Slavic tribes to the Baltic Sea. The pirates devastated mostly Danish islands. In 1135, the Norwegian city Kungahälla was captured and burned by the Prince Ratibor I of Pomerania. In 1153, the capital city of Denmark, Roskilde, was attacked by pirates. The main bases of the robbers were Starigard, Wolgast, Szczecin and Rügen Island. The Slavic piracy ended with the Danish conquest of Rügen and Pomerania in the end of the 12th century, German conquest of the Obotrites around the same time, and the German eastward expansion. The information about the Slavic pirates is contained in Helmold's Cronic, Heimskringla by Snorri Sturluson, Deeds of Bishops of the Hamburg Church by Adam of Bremen, and Gesta Danorum by Saxo Grammaticus.