in 1152, and began a reign which was disturbed by wars with
his nobility and by expeditions into Italy to subdue the
revolts of the city republics of Lombardy against imperial
authority. During his first expedition to Italy, 1154-1155,
Barbarossa soon crushed all opposition and was crowned
Emperor of the Holy Roman Empire, at Rome, by Pope Hadrian
IV. During his second expedition, 1158-1162, he destroyed
the city of Milan and dispersed the inhabitants, who sought
refuge in cities with which they had formerly been at
enmity. Barbarossa's violence antagonized the Italians, and
they combined in the Lombard League to drive him out of
Italy. He was excommunicated by Pope Alexander III, who
succeeded Hadrian in 1159, and to inaugurate the league a
town named Alessandria in honor of the Pope was founded on
the Piedmont frontier. In the expedition of 1166-1168
Barbarossa, who had set up an antipope, captured Rome and
enthroned Paschal III as pope. His triumph however, was
shortened by a pestilence which decimated his troops, and
thence began a series of reverses which ended in the
ascendency of the Lombard League.

No sooner had Frederick passed through North Italy on the way to his
triumph and ultimate humiliation in Rome than the formation was begun
of that greater Lombard League which was to prove so terrible and
invincible an enemy. Cremona was, according to the Emperor's own
account, the prime mover in the matter. Mantua, Bergamo, and Brescia
joined with that city, and bound themselves to mutual protection. The
league, which was to last for fifty years, was not openly hostile to
the Emperor; fidelity to him, indeed, was one of the articles of its
constitution. But only such duties and services were to be performed