The Ottonian dynasty had supported eastward expansion…

The Ottonian dynasty had supported eastward expansion of the Holy Roman Empire towards Wendish (West Slavic) lands during the tenth century.

The campaigns of King Henry the Fowler and Emperor Otto the Great had led to the introduction of burgwards to protect German conquests in the lands of the Sorbs.

Otto's lieutenants, Margraves Gero and Hermann Billung, had advanced eastward and northward respectively to claim tribute from conquered Slavs.

Bishoprics had been established at Meissen, Brandenburg, Havelberg, and Oldenburg to administer the territory.

A great Slavic rebellion in 983 had reversed the initial German gains, however.

While the burgwards had allowed the Saxons to retain control of Meissen, they had lost Brandenburg and Havelberg.

The Elbe River had thus become the eastern limit of German-Roman control.

The Christianization of Wagria had begun under Unwan, Archbishop of Bremen, in the 1020s.

By the early twelfth century, the Archbishoprics of Bremen and Magdeburg had begun to seek the conversion of the pagan Slavs to Christianity through peaceful means: notable missionaries include Vicelin of Oldenburg, Norbert of Xanten, and Otto of Bamberg.

Vicelin, a Christian priest, had first begun to evangelize the Wagri and Wilzi with the permission of the Obrodite prince, Henry, who was reigning from the site of present Lübeck, around 1126.

Secular Saxon princes seeking Slavic territory, lacking support from the Salian dynasty of the Holy Roman Empire, had found themselves in a military stalemate with their adversaries.

Christians, especially Saxons from Holstein, and pagans raid each other across the Limes Saxonicus, usually for tribute.

In the years following Vicelin's mission, the Emperor Lothair III had thoroughly encastellated Wagria.

From 1140-43, Canute Lavard and the Holsteiners had invaded it and taken Pribislav and Niklot, the Wagrian leaders, away in chains.

Count Adolf II of Holstein and Henry of Badewide take control of Polabian settlements that will soon become Lübeck and Ratzeburg; Vicelin had subsequently been installed as bishop at Oldenburg.

Adolf had sought peace with the chief of the Obodrite confederacy, Niklot, and encouraged German colonization and missionary activity in Wagria.

Henry the Lion and Adolf II of Holstein had divided the newly conquered Slav lands between them in 1143: Polabia with Ratzeburg had gone to Henry, while …