Frederick pitched his camp in the plain of Roncaglia and there received representatives from the Lombard towns, who had many and grievous complaints to make of the conduct of their neighbors, especially of the arrogant Milan. We get a hint of the distant commerce of the maritime cities when we read that Genoa sent gifts of ostriches, lions, and parrots. Frederick made a momentary impression by proceeding, upon the complaint of Pavia, to besiege and destroy the town of Tortona. As soon as he moved on to Rome, Milan plucked up courage to punish two or three neighbors who had too enthusiastically supported the emperor; it also lent a hand to Tortona's hapless citizens in rebuilding their city. [Sidenote: Frederick and Pope Hadrian.] When the pope, Hadrian IV, and the emperor first met there was some bitter feeling because Frederick hesitated to hold the pope's stirrup. He made no further objection, however, when he learned that it was the custom. Hadrian was relying upon his assistance, for Rome was in the midst of a remarkable revolution. Under the leadership of the famous Arnold of Brescia,[121] the city was attempting to reëstablish a government similar to that of the times when the Roman senate ruled the civilized world. It is needless to say that the attempt failed, though Frederick gave the pope but little help against Arnold and the rebellious Romans. After receiving his crown, the emperor hastened back to Germany and left the disappointed Hadrian to deal with his refractory people as best he might. This desertion and later misunderstandings produced much ill feeling between the pope and Frederick. [Sidenote: The assembly at Roncaglia, 1158.] [Sidenote: Its decision as to the rights (_regalia_) of the emperor over the Lombard towns.]