Although Otto II had succeeded peacefully to the throne, internal divisions of power still remained unaddressed. During his first seven years as Emperor, he was constantly occupied with maintaining Imperial power against internal rivals and external enemies. The domestic problems Otto the Great faced between 963 and 972 had not been resolved by his death. The Saxon nobility continued to resist the Archdiocese of Magdeburg located along the Empire's eastern border. Though established by Otto I, the exact details of the diocese's boundaries were left to Otto II and his aides. Otto II's marriage to the Byzantine Princess Theophanu proved to be to his disadvantage because the Saxon nobles felt it distanced the Emperor from their interests. Among Otto II's chief advisors, only the Saxon Bishop Dietrich I of Metz had close connections with the old Saxon nobility. His other advisers lacked support from the Empire's various dukes. The Archbishop of Mainz, Willigis, appointed in 975, who had been Otto II's advisor since Otto the Great's second expedition into Italy in the 960s, had not been born into a noble family. Hildebald of Worms, who had been appointed as Otto II's Chancellor in 977 and then as Bishop of Worms in 979, was also not from a noble family. Otto the Great also failed to clarify affairs in Italy prior to his death. Otto died soon after the appointment of Pope Benedict VI in 973. In 974 Benedict was imprisoned in the Castel Sant'Angelo, the stronghold of the Crescentii family. When Otto II sent an imperial representative, Count Sicco, to secure his release, Crescentius I and Cardinal-Deacon Franco Ferrucci, who would subsequently become Boniface VII, an antipope, had Benedict murdered while still in prison. Following his coronation, a rift developed between Otto II and his mother, the Dowager Empress Adelaide of Italy. From the death of Otto the Great until Easter 974, Adelaide accompanied the Emperor at all times, traveling throughout the Empire with him. However, Otto II's mother and his wife Theophanu each mistrusted the influence the other held over the Emperor, causing friction within the Imperial household. A final meeting between Otto II and Adelaide was arranged shortly before Pentecost in 978, but a peaceful outcome was not achieved, forcing Adelaide to retire to Burgundy and to the protection of her brother King Conrad of Burgundy. Conflict with Henry II Otto II sought continued peace between himself and