son of the Margrave Otto the Rich, of Ascania, became bishop of Havelberg in 1126, and archbishop of Ravenna in 1154; was Apocrisiarius of Emperor Lothaire II, and was sent as an ambassador to the emperor of Constantinople for the purpose of effecting a union between the Roman and Greek Churches. He died in 1159. He wrote Three Books of Dialogues with Nicetas, archbisbop of Nicomedia, about the points in dispute between the Greek and Roman Churches, given by D'Achery in the Spicilegium, 1, 161 (new ed.). — Dupin, Hist. Eccl. Writers, 2, 365; Cave, Hist. Lit. anno 1149; Landon, Eccl. Dict. s.v.