But the fierce heathen spirit, which had been strengthened by Boleslav the Cruel, could not be suppressed at once either by his conversion, or by the probably sincerer piety of his son. It is now that the strong and cruel aristocracy of Bohemia begin to show their power both against king and people. Even in heathen times we hear of at least one family who claimed a sort of equality with the royal line, and who continued during the tenth and eleventh centuries to play much the same part as that of the Douglases in Scotland in the fourteenth and fifteenth centuries. There was, however, one important difference between the cases. With all their selfishness and unscrupulousness, the Douglases always stood by Scotland against its external enemies, while the Vrs̆ovici were continually betraying Bohemia to Pole or German in order to gain their own ends. Nor were the Vrs̆ovici the only specimens of a lawless and cruel class; and Boleslav the Pious and Bishop Dettmar soon incurred the hatred of that class. The bishop, however, did not long survive his appointment; and he was soon to be succeeded by a man far more notable in Bohemian history. This man was Vojtĕch, the son of a powerful Bohemian noble, who was as distinguished for his virtues as for his wealth and rank. Vojtĕch, by the advice of Dettmar, had been sent by his parents to study at Magdeburg; and on his entrance into the clerical profession, he had received from the Archbishop of Magdeburg his name of Adalbert. When he returned to Bohemia, he was called to succeed Dettmar in the bishopric of Prague. He soon began to denounce the state of morals around him. Divorce was frequent; impurity of all kinds terribly rife; and the nobles, not content with oppression at home, were constantly selling their unfortunate dependants into slavery. The stern denunciations of Adalbert soon roused against him the hatred of his own class, which was increased in bitterness by the rivalry between his family and that of the Vrs̆ovici.
On one occasion a woman, whom he had saved from her angry husband and sent into a nunnery, was dragged out and murdered by her husband. Boleslav desired to repress such violence by the sword; Adalbert at first persuaded him to abstain from bloodshed; but, when the insurgent nobles built a fortress on the banks of the Elbe, from which they harassed all the Christians who came that way, the king felt bound to act; so he marched against the insurgents and signally defeated them. Adalbert, horrified at being in any way the cause of bloodshed, fled to Pannonia, which had now been conquered by the Hungarians.