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 as had been customary in the time of Conrad III; so the cities practically renounced the Roncaglian decrees and declared themselves in revolt.
From the beginning, too, the league took sides with Alexander. But its most daring act of insubordination was the leading back in triumph of the Milanese to the scene of their former glory. The outer walls of Milan had not been entirely levelled to the ground, and the city arose as if by magic from her ruins. Bergamo, Brescia, and Cremona lent her efficient aid in the work of restoration.
A sculpture executed in 1171 by order of the consuls, and showing the return, accompanied by their allies, of the exiles, is still to be seen in Milan, near the Porta Romana. How few of those who look on it to-day realize what that return meant to the long-suffering citizens, and what premonitions of evil to come must have gone with them.
The Lombard League spread rapidly. Lodi, after much demur and after being surrounded by an army, was forced to join it. Piacenza needed no constraint, and Parma yielded after some opposition. Including Milan there were soon eight cities in the confederation. The imperial officials were disavowed and the old consular rule reëstablished, while everywhere Alexandrine bishops replaced those that had been invested by Victor and Paschal.
Returning almost in disgrace from Rome, Frederick took up the struggle against the revolted cities, sending an appeal for reinforcements to Germany. But an attack on Milan proved fruitless, as did also one on Piacenza, and the Emperor was soon forced to intrench himself in Pavia. His position became more and more desperate, the more so as the new archbishop of Milan, Galdinus, unfolded a great activity in favor of Alexander. The Pope named him apostolic legate for the whole of Lombardy, and it was doubtless due to his influence that at this time the Verona coalition formally joined the Lombard League.