The German Emperor was naturally indignant at the murder of his faithful _protégé_; and he exacted from Boleslav, as the price of peace, the recall of the banished Christians, the renewal of the tribute which he had just remitted to Wenceslaus, and an oath of allegiance, such as had hitherto been paid to the Emperor only by German princes. Boleslav was apparently induced to submit to these severe terms, partly by his fear of the power of the Emperor, partly by a sense of the danger which was still threatening the civilised States of Europe, a danger which could only be faced by an alliance with the new ruler who had arisen in Germany. For while Bor̆ivoj and his successors had been struggling to assert their power over their heathen subjects, the old Saxon kingdom had succeeded in producing a champion of European freedom and civilisation. Henry the Fowler had thrown off the effete yoke of the Franks, and rallied the Germans under his banner; he had then routed the Hungarians at the celebrated battle of Merseburg, and had founded towns, by which a new order of civilisation was being introduced into Germany. His son Otto was vigorously carrying on the struggle against the Hungarians; and Boleslav, however much he might dislike foreign rule, saw that an alliance with Otto was the only hope for his country. The Hungarians were now advancing into Bohemia, and Boleslav encountered them on the frontier and completely defeated them. He then proceeded to suppress a robber tribe who had given much trouble to Wenceslaus, and who had established a castle on the borders of Bohemia, from whence they had harassed the country. The chroniclers declare that Drahomíra was swallowed up in an earthquake, and perhaps her death removed the chief anti-Christian influence in the life of Boleslav; for, to whatever motives of conviction or policy the change may have been due, it is evident that, from this time forward, he not merely abandoned his persecution of the Christians, but used all his power to encourage their influence. The son whose baptism had been the occasion of the murder of Wenceslaus, became a monk; while the second son was trained with such effect in the principles of Christianity that he afterwards gained the name of Boleslav the Pious. But to the father of these princes the Bohemian chroniclers are as inexorable as they had been to Svatopluk; and, while Wenceslaus is remembered as one of the chief national saints of Bohemia, his brother lives in history as Boleslav the Cruel.