North of Bohemia, in the country lying between the Baltic, the Elbe, and the Oder, Otto had established a series of marks or border-lands in which he had built towns, introduced German colonists, and founded bishoprics which he had grouped round a new Metropolitan at Magdeburg. Here for nearly a century and a half the House of Billung did much to keep under the surging tide of paganism. It was the ambitions of Adalbert, Archbishop of Bremen (1043-72), which for a time caused a serious heathen reaction in this quarter. He was the rival of Hanno of Koln for influence at the Court during Henry IV's minority. As the most northern German Metropolitan he aspired to set up a patriarchate in Northern Europe. He met with considerable success in Scandinavia.
[Sidenote: Scandinavia.]
The Christianisation of Denmark had been completed under Cnut, who also ruled over England (1014-35). Norway was also being rapidly converted; but the forcible methods of King Olaf, who afterwards became the patron saint of his country, roused discontent. Cnut added Norway to his dominions, and was anxious to make his realm ecclesiastically independent. He established three bishoprics in Denmark, but did not get his own metropolitan, and his empire fell asunder at his death. Adalbert made a close alliance with Swein of Denmark, and thus kept the Danish Church dependent. Harold Hardrada struggled against Adalbert's attempts to assert his power in Norway. Sweden had accepted Christianity under Olaf Stotkonung, i.e. the Lap-King, who died in 1024. But until towards the end of the eleventh century heathenism continued to maintain itself, and the difficulties of the Christian party were considerably increased by the assertive policy of Bremen. Adalbert's schemes were wide-reaching. He sent bishops to the Orkneys, to Iceland, and even to Greenland, of which the last two lands had been converted by missionaries from Norway and ultimately became subject to the Metropolitan of Norway.
[Sidenote: Wends.]
But the real mischief of Adalbert's ambitious schemes was apparent east of the Elbe. He founded the bishopric of Hamburg, and held it in addition to Bremen. He sent bishops to Ratzeburg and Mecklenburg across the Elbe. He encouraged Henry IV's schemes against the Saxons in order to diminish the power of the House of Billung, who were his rivals in that quarter. The various tribes of the Wends—Wagrians, Obotrites, Wiltzes—had been drawn together into one kingdom under Gottschalk (1047-66), himself a Christian, who founded churches and monasteries, and has been likened to Oswald of Northumbria in that he interpreted the missionaries' sermons to his heathen subjects. This dominion had been established under the protection of the Saxon dukes. But Henry IV's quarrels with Saxony distracted the attention of the Billungs and their followers; and Gottschalk's death was followed by a heathen reaction in which, together with the extirpation of other marks of Christianity, the bishoprics were destroyed, and among them Adalbert's own foundation of Hamburg. This was the beginning of the end. Adalbert's successor had to be content with Bremen alone. Moreover, in the investiture struggle he was loyal to Henry IV; and since Eric of Denmark declared for the Pope, Urban II made the Danish prelate of Lund the Metropolitan of the North (1103). This arrangement caused discontent in the two other Scandinavian kingdoms, and ultimately Eugenius III sent Cardinal Breakspear, the future Hadrian IV, on a mission which resulted in the establishment of Nidaros or Drontheim as the see of a primate for Norway, and of Upsala in a similar capacity for Sweden. It may be mentioned in connection with this point that Finland owed its conversion to Sweden very shortly afterwards, though the Swedish attempts in Esthonia failed.
[Sidenote: Their final conversion.]
Meanwhile among the Wends Gottschalk's son revived his father's authority and contact with German civilisation; but after 1131 the Wendish kingdom fell to pieces, and from that moment we can mark the steady advance of German power to the Oder. The Billung line of Saxon dukes had become extinct in 1106, and Henry V had given the ducal name to Lothair, who succeeded him as Emperor, and who as Duke aimed at building up a strong dominion in north-eastern Germany. As Emperor he took up the civilising rôle of Otto the Great and encouraged the Germanisation of the Slavs. The actual work was done by his chief adviser Norbert, whom he had almost forced to become Archbishop of Magdeburg. He acted in conjunction with Albert the Bear, a descendant in the female line of the Billung dukes and Margrave of the Northmark, who himself founded bishoprics among his immediate neighbours the Wiltzes. Albert's soldiers prepared the way for Norbert's Premonstratensian canons, and bishoprics were founded with so little regard for division of territory, even in Poland and Pomerania, that both Gnesen and Lund found themselves for a time subordinated to Magdeburg. Two names are especially associated with the conversion of the Wends. In 1121, under the patronage of Lothair who was not yet Emperor, Vicelin began his work among the Wagrians, and in 1149 he became their Bishop with his see at Oldenburg. He died in 1154. It was under the auspices of Henry the Lion, now Duke of Saxony, that Berno preached to the Obotrites, converting the Wendish Prince and becoming Bishop of Mecklenburg. The gradual advance of German colonisation had weakened the Wendish resistance and prepared the way for this restoration of Christianity. Henry the Lion finished the work. In alliance with Waldemar II of Denmark he repeated with greater completeness the work of founding bishoprics, establishing houses of Premonstratensians, whose missionary activity was now shared by the Cistercians, building towns and introducing colonists, until the whole country between the Northmark and the Baltic was included in his Saxon duchy.
[Sidenote: Pomerania.]
The fall of Henry the Lion was not followed by any anti-German reaction; and meanwhile the work of conversion had been going forward among the Slavs beyond the Oder. The first attempts of the Poles to influence their troublesome Pomeranian neighbours failed. The ultimate success of a mission was due to a German. Otto, a native of Suabia, began as a schoolmaster in Poland. From chaplain to the Polish Prince the Emperor Henry V made him Bishop of Bamberg (1102); and, when Boleslas III had subdued part of Pomerania and found his bishops unwilling to attempt its conversion, he offered the task to Otto of Bamberg who, although an old man, undertook it with the consent of the Pope and the Emperor. He paid two visits—in 1124 and 1128—both to Western Pomerania, and established the bishopric of Wollin. The conversion was naturally imperfect, but the country never relapsed. The fierce islanders of Rgen could not then be touched, but ultimately gave way in 1168 before the combined secular and spiritual weapons of the Danish rulers.
[Sidenote: Livonia.]