Rome, Frederick, who had left from the North with the title of King of Germany, was harshly contested by the people of the city; in response, the emperor reacted by stifling the revolt in blood. Following this episode, and to Frederick's military campaign, the relations between the Holy Roman Empire and the Papacy began to crack. During the return trip to Germany, the emperor destroyed Spoleto, accused of having paid the fodro, that is, the taxes to be paid to the sovereign, with a false currency. Already during this first descent, the difference between Frederick and his predecessors was felt. In fact, Barbarossa showed a strong aversion to municipal autonomies: his will was to restore effective power over Northern Italy. The second descent, which began in June 1158, was originated by the rebelliousness of Milan and the allied municipalities to accept imperial power. This long expedition began with the attack of Frederick Barbarossa in Milan and his allies of the Milanese countryside: after defeating Brescia, which was a Milanese company, and having freed Lodi from the Milanese yoke, Barbarossa directed the attack to the Milanese capital, who agreed to surrender (8 September 1158) to avoid a long and bloody siege. Milan again lost the conquests made in previous years (Como, Pavia, Seprio and Brianza), but it was not razed. Frederick Barbarossa, then, summoned a second diet to Roncaglia (autumn 1158) where he reiterated the imperial dominion over the municipalities of Northern Italy, with the authority of the sovereign that imposed itself on that of the local institutions, establishing, among other things, that the regalie were entirely paid to the sovereign. The proclamations of this second diet of Roncaglia had disruptive effects on the Italian communes, which immediately rebelled. After receiving reinforcements from Germany and having conquered several riotous municipalities in Northern Italy during a military campaign that lasted a few years, Barbarossa turned its attention to Milan, which was first besieged in 1162 and then, after its surrender (1 March), completely destroyed. A similar fate fell on several cities allied to Milan. Frederick then exacerbated the grip of imperial power on Italian cities, going beyond the provisions decided during Roncaglia's second diet: he set up a bureaucratic structure run by officials who responded directly to the emperor instead of the municipal autonomies, which were virtually suppressed, and established an imperial-nominated podestà at the head of the rebel cities. Meanwhile, Pope