 In 1148, Otto married Judith of the Piast dynasty, sister of the Dukes of Poland Boleslaw IV and Mieszko III.Arrangements for the marriage were agreed upon during the Wendic Crusade (one of the Northern Crusades) in a meeting of January 6, 1148, in which Archbishop Friedrich of Wettin participated besides Otto and the two Polish dukes.According to Partenheimer (2003), the marriage was contracted in connection with the Ascanian efforts to support the Piast dynasty in opposition to King Conrad, who supported Wladyslaw II as legal ruler of Poland.