In 976, Otto II had deposed Henry II as Duke of Bavaria and imprisoned him. In early 984, Henry II escaped from his imprisonment by the Bishop of Utrecht. Free from his confinement, he seized the infant Otto III and, as a member of the ruling Ottonian dynasty, claimed the regency of the Empire for himself. Henry II eventually went so far as to claim the German throne outright, obtaining the allegiance of Mieszko I of Poland and Boleslaus II, Duke of Bohemia. Henry II's claims were supported by Archbishop Egbert of Trier, Archbishop Gisilher of Magdeburg, and Bishop Dietrich I of Metz. Otto III's right to the throne, however, was supported by Archbishop Willigis of Mainz and the Dukes of Saxony, Bavaria, and Swabia. The threat of war from Willigis and Conrad I, Duke of Swabia forced Henry II to relinquish Otto III on June 29, 984 and to respect the regency of Theophanu.