Circipania came under control of the Pomeranian dukes at about this time. Despite this vassalage, Henry again sieged Demmin in 1177 when he allied with the Danes, but reconciled with the Pomeranian dukes thereafter. After the 1147 Wendish crusade and the 1164 Battle of Verchen, the duchy (at least the western parts) had joined Henry the Lion's Duchy of Saxony. Following internal struggles, Henry fell against Holy Roman Emperor Frederick Barbarossa in 1181. Bogislaw I took his duchy as a fief directly from Barbarossa in the same year. At that time, the duchy was also referred to as Slavinia () (yet this was a term applied to several Wendish areas such as Mecklenburg and the Principality of Rügen). The duchy remained in the Empire, although Denmark managed to take control of the southern Baltic including the Duchy of Pomerania from the 1180s until the 1227 Battle of Bornhöved. From the North, Denmark attacked Pomerania. Several campaigns throughout the 12th century (in 1136, 1150, 1159 and throughout the 1160s) culminated in the defeat of the Principality of Rugia in 1168. The island of Rügen and the surrounding areas between the Recknitz, Peene and Ryck rivers were the settlement area of the West Slavic Rani (or Rujani) tribe. After Otto von Bamberg's mission, only the Rani principality of Rugia (Rügen) remained pagan. This was changed by a Danish expedition of 1168, launched by Valdemar I of Denmark and Absalon, archbishop of Roskilde. The Danish success in this expedition ended a series of conflicts between Denmark and Rügen. The Rügen princes, starting with Jaromar I, became vassals of Denmark, and the principality would be Denmark's bridgehead on the southern shore of the Baltic for the next centuries. The 1168 expedition was decided when after a Danish siege of the burgh of Arkona, a fire broke out leaving the defendants unable to further withstand the siege. Since Arkona was the major temple of the superior god Swantewit and therefore crucial for the powerful clerics, the Rani surrendered their other strongholds and temples without further fighting. Absalon had the Rani hand out and burn the wooden statues of their gods and integrated Rügen in the Diocese of Roskilde.