Henry Julius actually took over administration of the Halbertstadt prince-bishopric in 1578, he became active as a temporal as well as spiritual ruler. He improved general education in the episcopal lands, and completed the implementation of the Protestant Reformation begun by his father, although he allowed Catholic office holders to keep their privileges — except that he strictly prohibited priests from having mistresses. In view of his moderate policies, he also was offered the position of an administrator of the Minden prince-bishopric and was elected by the cathedral chapter in 1582. Nevertheless, expectations were disappointed, when Henry Julius ordered that all sermons ought to be preached according to the Augsburg Confession. When he resigned from office three years later, to marry the Wettin princess Dorothea of Saxony, he left a virtual Lutheran diocese.