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