The government of the towns of Lombardy fell, after Charlemagne's time, into the hands of their respective bishops, who exercised the prerogatives of counts. Under the bishops the towns flourished within their walls and also extended their control over the neighboring districts. As industry and commerce increased, the prosperous citizens, and the poorer classes as well, aspired to some control over the government. Cremona very early expelled its bishop, destroyed his castle, and refused to pay him any dues. Later Henry IV stirred up Lucca against its bishop and promised that its liberties should never be interfered with henceforth by bishop, duke, or count. Other towns threw off the episcopal rule, and in practically all of them the government came at last into the hands of municipal officials elected by those citizens who were permitted to have a hand in the government. [Sidenote: The turmoil in the Italian towns; their remarkable civilization.] [Illustration: Italian Towns in the Twelfth Century] The more humble artisans were excluded altogether from a voice in city affairs. Their occasional revolts, as well as the feuds between the factions of the nobles,--who took up their residence in the towns instead of remaining on their estates,--produced a turmoil which we should think intolerable in our modern peaceable cities. This was greatly increased by bitter wars with neighboring towns. Yet, in spite of incredible disorder within and without, the Italian towns became centers of industry, learning, and art, unequaled in history except by the famous cities of Greece. They were able, moreover, to maintain their independence for several centuries. Frederick's difficulties in playing the emperor in Italy were naturally greatly increased by the sturdy opposition of the Lombard towns which could always count on a faithful ally in the pope. He and they had a common interest in seeing that the power of the king of Germany remained purely nominal on their side of the mountains.[120] [Sidenote: Frederick's first expedition to Italy, 1154.] 68. Milan was the most powerful of the Lombard towns and was heartily detested by her neighbors, over whom she was constantly endeavoring to extend her control. Two refugees from Lodi brought word to the newly elected emperor of Milan's tyranny. When Frederick's representatives reached the offending city they were insulted and the imperial seal was trampled in the dust. Like the other towns, Milan would acknowledge the supremacy of the emperor only so long as he made it no trouble. The wish to gain the imperial crown and to see what this bold conduct of Milan meant, brought Frederick to Italy, in 1154, on the first of six expeditions, which together were to occupy many years of his reign.