Early in his reign, by settling a dispute over the crown of Denmark, Frederick brought the king of that country once more into the position of a German vassal. Having spent the year 1156 in settling the Bavarian question and in enforcing order in the Rhineland and elsewhere, the emperor marched into Poland in 1157, compelled its ruler, Boleslaus IV., to do the homage which he had previously refused to perform, and in return for services rendered during the campaign and for promises of future aid, raised the duke of Bohemia to the rank of a king, a change which in no way affected his duties to the German crown, but which gave him a certain precedence over other vassal princes. The king of Hungary, too, although no attempt was made to subdue him, became a useful ally. Thus the fame of Germany in the neighbouring countries, which had been nearly destroyed during the confusion of Henry IV.'s reign, was to a large extent restored. Frederick asserted his authority in Burgundy or, as it was sometimes called, Franche Comté. In Germany itself internal order was established by a strict appliance of the existing laws against those who broke the peace, fresh orders for its observance were issued, and in Frederick the robber nobles found a most implacable enemy. The cities, too, flourished during this reign. The emperor attached them to himself by granting to many of them the very liberties which, by a strained interpretation of his imperial rights, he withheld from the cities of Lombardy. Yet, notwithstanding his policy, in these directions the German nobles appear to have been enthusiastically devoted to Frederick. Time after time they followed him to Italy, enduring serious losses and hardships in order that he might enforce claims which were of no advantage to them, and which, previously, had been a curse to their nation. Their loyalty is well illustrated by the famous scene at Besançon in October 1157. During a meeting of the diet a papal legate read a letter from Pope Adrian IV., which seemed to imply that the Empire was a papal fief. Indignant murmurs rose from the assembled nobles, and the life of the legate was only saved from their fury by the intervention of the emperor himself. The secret of Frederick's great popularity was partly the national pride excited by his foreign achievements, partly the ascendance over other minds which his genius gave him, and partly the conviction that while he would forego none of his rights he would demand from his vassals nothing more than was sanctioned by the laws of the Empire.