Henry was repeatedly summoned to answer his accusers, but did not deign to appear. On the contrary he prepared to raise up for himself allies and to besiege the castles of those who would not join him. His own lands were thereupon laid waste by his private enemies, and that with the Emperor's consent. But Halberstadt, which took part in one of these plundering expeditions, suffered a terrible vengeance at the hand of the enraged Guelf. In one destructive blaze the city, churches and all, was reduced to ashes. In the war that he was now waging Henry did not hesitate to call in even the Wends to his aid, but Westphalia was soon lost to him, and only in East Saxony was he able to maintain himself.
At a diet held in Wuerzburg in January, 1180, the Emperor laid the question before the princes what was to be done to one who had refused, after having been three times summoned, to come before the imperial tribunal. The answer was that he was to be deprived of all honor, to be judged in the public ban, and to lose his duchy and all his benefices. Thus was final sentence passed on the chief man in Germany next to the Emperor himself.
An imperial army was now raised and several fortresses were besieged. No battle took place, but the fact that Frederick had a large force at his command was sufficient to cause defection in the ranks of Henry's allies. In 1181 the Emperor's army marched as far as Lubeck, which city, Henry's proudest foundation, was forced to submit. The whole region north of the Elbe followed Lubeck's example, and Henry was soon forced to confess that his cause was hopeless. He laid down his arms, and was summoned to a diet at Erfurt to learn his fate. Here he fell on his knees before Frederick, who, with tears in his eyes, raised him and kissed him in token of peace.
He was made to surrender all his possessions with the exception of Brunswick and Luneburg. He was to go into exile, and to bind himself by an oath not to return without the Emperor's permission. He soon afterward passed over to Normandy, where he stayed for two years with his father-in-law, Henry II. He then passed over with the latter to England.
The years immediately following the Congress of Venice were, strange to say, the most brilliant period of Frederick's reign. It was, after all, only his ideals that had suffered, and a time of prosperity now settled down upon the nation.
With Alexander the Emperor remained on friendly terms; but the Pope in 1181 died in exile, having been forced by the faithless Romans, as Gregory VII had been a century before, to flee the holy city.
The peace with the Lombard towns was signed at Constance within the six years agreed upon, on June 23, 1183. The communal freedom for which they had fought so long was now accorded them; the Emperor gave up all right to the regalia and recognized the Lombard League. His dream of becoming a second Justinian had not been realized.
The cities received the privilege of using the woods, meadows, bridges, and mills in their immediate vicinity, and of raising revenues from them; the jurisdiction in ordinary, civil, and criminal cases; the right of making fortifications. The Emperor was, to a certain extent, to be provided for when he chose to come to Italy; but he promised to make no long stay in any one town. The cities were to choose their own consuls, who were to be invested with their dignity by the Emperor or his representatives. The ceremony, however, was to be performed only once in five years. In important matters where more than a certain sum was at stake, appeals to the Emperor were to be allowed.
With the city of Alessandria, so long to him a thorn in the flesh, Frederick had already come to a separate agreement by consent of the league. The city was, technically, to be annihilated, and then to be refounded; it was no longer to bear the name of the Pope, but that of the Emperor. Alessandria was to become Cæsarea; yet none of the Inhabitants was to suffer by the change.
The treaty is extant; it provided that the people should leave the
city and remain without the walls until led back by an imperial envoy.
All the male inhabitants of Cæsarea were then to swear fealty to the
Emperor and to his son Henry VI.