Wichmann was the second son of the
Saxon count Gero of
Seeburg (d. 1122) and his wife Matilda, a daughter of the
Wettin count
Thimo the Brave. He studied theology at the
University of Paris before becoming a canon in
Halberstadt. Throughout his long ecclesiastical career, he was a loyal supporter of the
Hohenstaufen emperor
Frederick Barbarossa against
Pope Alexander III and an implacable military leader against the emperor's foes in the northeast, especially the
Welf duke
Henry the Lion. Wichmann was elected Bishop of Naumburg-Zeitz in 1149 and ordained the next year. He made large donations to the monasteries of
Pforta and
Zeitz. A regular guest at the court of King
Conrad III of Germany, he was quickly appointed to the Archdiocese of Magdeburg by Conrad's nephew, the newly crowned King Frederick Barbarossa in 1152. Wichmann initially had to overcome the resistance by
Pope Eugene III and his successor
Anastasius IV; nevertheless, he immediately endeavoured to extend his diocese and its economy, and actively promoted trade within the cities. In 1157, he allied with the
Ascanian margrave
Albert the Bear to re-conquer and
Germanise the cities of
Brandenburg and
Jüterbog, whose vicinity he conquered and colonised with
Flemish settlers (cf.
Fläming). In 1170 he granted large estates to the newly established
Cistercian monastery of
Zinna. He attended the 1160 Council of Pavia, supporting the election of
Antipope Victor IV. In 1164, he undertook a pilgrimage to
Palestine and fell for a time into
Turkish hands. After supporting the election of
Antipope Paschal III, he tried to adopt the position of a mediator with
Pope Alexander III. In 1166, Wichmann joined the German
princes in war with Duke Henry the Lion, but he succeeded only in seeing his lands devastated. In 1175, he supplied auxiliaries to the emperor for his
Italian campaign. He was in
Venice negotiating
the peace treaty in 1177. In 1178, he was back in Saxony for the war against Henry the Lion. He strongly worked for Henry's deposition and ban in 1180 and greatly profited from its actualisation, becoming the principal secular authority in Saxony after. He remained deeply predisposed against the Welfs, however. In 1180 and 1185, he gave parts of his extensive possessions to
Seitenstetten Abbey in
Austria and to the
Bishopric of Passau. He died on 25 August 1192 in the proximity of
Köthen and was buried in his own
cathedral. The city and diocese of Magdeburg had fully bloomed under his oversight. Wichmann is also credited with the first codification of
magdeburg town law in 1188. ==Sources==