One of several Slavic tribes living east of the river Elbe in what is now northeastern Germany. The Polabians were loosely united with the Wagrians to the north and the Abodrites to the east.
The Polabians are mentioned by the historian Adam of Bremen in his Historia Hammaburgensis ecclesiae as being subject to the archbishopric of Hamburg-Bremen. Adam also refers to Ratzeburg as their main city, a statement repeated by Helmold of Bosau in the opening chapters of his Chronica Slavorum. Helmold also states that the Polabians had originally been subjected to the bishopric of Oldenburg in Holstein, originally established around 972 by Otto I, Holy Roman Emperor. Various rebellions among the Abodrites in the last two decades of the tenth century, however, led to the destruction of this bishopric, and it was not until around 1062 that it was reestablished, this time, however, only as a bishopric for the Wagrians to the north. To the south new bishoprics were founded in Ratzeburg for the Polabians and in Mecklenburg for the tribes living in the coastal regions of the northeast.
Even though some of the princely families now nominally accepted the Christian faith, there was no general acceptance of Christianity among the Slavic tribes for several decades to come.
In 1129 the German king Lothar III had entrusted the Abodrite kingdom to Knud Lavard, duke of Schleswig, but when Knud was murdered in 1131, Prince Pribislaw became the new ruler of the Polabians and Wagrians. Though presumably nominally a Christian, Pribislaw forbade any further missionary activities among his people. A few years later he invaded neighboring Holsatia (part of modern Holstein). This was to be the last attack into Holsatia by the Slavs, and in the winter of 1138-1139 Count Henry of Badewide led the Holsatian levies into Wagria, ravaging the region. In 1143 Henry was then given the land of the Polabians, which now became known as the county of Ratzeburg. Together with Count Adolf II of Schauenburg, who had been given parts of Wagria, Henry colonized the newly conquered land by bringing in peasants from Holsatia, Frisia, Westphalia, Flanders, and Holland, thus connecting the land of the Polabians firmly with the duchy of Saxony and the German kingdom.