Anselm of Havelberg

Anselm of Havelberg (c. 1100 – 1158) was a German bishop and statesman, and a secular and religious ambassador to Constantinople. He was a Premonstratensian, a defender of his order and a critic of the monastic life of his time, and a theorist of Christian history. According to Friedrich Heer, "the peculiar course of Anselm's life made this much-travelled man the theologian of development, of progress, of the right of novelty in the Church".

Anselm's birthplace is uncertain. He was a pupil of Norbert of Xanten at Laon, and then was appointed to the Bishopric of Havelberg in the Northern March. Because Havelberg was then controlled by the Polabian Slavs, Anselm's provisional seat was in Jerichow. He served as papal legate and overall commander of the 1147 Wendish Crusade. After Havelberg was recovered by the Saxons during the campaign, cathedral construction was begun.

Anselm was sent by Lothair III, Holy Roman Emperor, to Constantinople in 1136. in the hope of a Byzantine alliance. He held theological discussions with Nicetas of Nicomedia, an account of which he wrote later as his Dialogues, at the request of Pope Eugenius III. His account tended to play down the theological differences, including the filioque clause, but was more stark on the political issues. A later encounter with Basil of Achrida in 1154 proved fruitless

...
Wikipedia