Editing Bolesław III Wrymouth (section)

===Political Background===
In 1125 [[Henry V, Holy Roman Emperor]] and [[King of Germany]], died. His successor, [[Lothair II, Holy Roman Emperor|Lothair of Supplinburg]], was embroiled in disputes over his inheritance, and became involved in papal politics. In 1130 there was a double election to the Apostolic See. Lothair supported [[Pope Innocent II]], hoping in this way to secure his own coronation.<ref name="Czapliński, p. 138">W. Czapliński, A. Galos, W. Korta: ''Historia Niemiec'', p. 138.</ref> Contrary to expectations, Lothair's Imperial coronation didn't end his disputes against the contenders for the German throne.<ref>W. Czapliński, A. Galos, W. Korta: ''Historia Niemiec'', p. 137.</ref>

In 1130 Bolesław controlled the areas situated on the left bank of the Oder river on the island of Rügen. Germany had designs on these lands, but its internal political situation and its involvement in a civil war in Hungary, made an armed conflict impractical. The death of King [[Stephen II of Hungary]] in 1131 had led to war between two claimants to the throne: [[Béla II of Hungary|Béla the Blind]] (son of [[Álmos, Duke of Croatia]]) and [[Boris Kalamanos|Boris]] (the alleged son of [[Coloman, King of Hungary|King Coloman]]). Boris sought the help of the Polish ruler, who hoped for a closer alliance with Hungary and cooperation with the Kievan princes (Boris was a son of a daughter of [[Vladimir II Monomakh]]). However, Bolesław overestimated his strength against Béla, who had the support of almost all his country. The Polish army faced the combined forces of Hungary, Bohemia, Austria and Germany in the Battle of the [[Sajó]] River (22 July 1132), where the coalition achieved complete victory over the Polish duke, who was forced to retreat.<ref name="Czapliński, p. 138"/>

The success in Hungary was used by the Bohemian ruler [[Soběslav I, Duke of Bohemia|Soběslav I]], an Imperial vassal, who during 1132–34, repeatedly invaded Silesia.<ref name="Szczur, p. 125"/> The question of Silesia's property was left to Lothair III. Around the same time, the bull ''Sacrosancta Romana'' of 1133 gave the Archbishopric of Magdeburg sovereign rights over the Pomeranian dioceses instituted by Bolesław.