Strengthened by their contest with Frederick Barbarossa, recognized in their rights as belligerent powers, and left to their own guidance by the Empire, the cities were now free to prosecute their wars upon the remnants of feudalism.  The town, as we have learned to know it, was surrounded by a serried rank of castles, where the nobles held still undisputed authority over serfs of the soil.  Against this cordon of fortresses every city with singular unanimity directed the forces it had formed in the preceding conflicts.  At the same time the municipal struggles of Commune against Commune lost none of their virulence.  The Counts, pressed on all sides by the towns that had grown up around them, adopted the policy of pitting one burgh against another.  When a noble was attacked by the township near his castle, he espoused the animosities of a more distant city, compromised his independence by accepting the captaincy or lieutenancy of communes hostile to his natural enemies, and thus became the servant or ally of a Republic.  In his desperation he emancipated his serfs, and so the folk of the Contado profited by the dissensions of the cities and their feudal masters.  This new phase of republican evolution lasted over a long and ill-defined period, assuming different characters in different centers; but the end of it was that the nobles were forced to submit to the cities.  They were admitted to the burghership, and agreed to spend a certain portion of every year in the palaces they raised within the circuit of the walls.  Thus the Counts placed themselves beneath the jurisdiction of the Consuls, and the Italic population absorbed into itself the relics of Lombard, Frank, and German aristocracy.  Still the gain upon the side of the republics was not clear.  Though the feudal lordship of the nobles had been destroyed, their wealth, their lands, and their prestige remained untouched.  In the city they felt themselves but aliens.  Their real home was still the castle on the neighboring mountain.  Nor, when they stooped to become burghers, had they relinquished the use of arms.  Instead of building peaceable dwelling-houses in the city, they filled its quarters with fortresses and towers, whence they carried on feuds among themselves and imperiled the safety of the streets.  It was speedily discovered that the war against the Castles had become a war against the Palaces, and that the arena had been transferred from the open Contado to the Piazza and the barricade.  The authority of the consuls proved insufficient to maintain an equilibrium between the people and the nobles.  Accordingly a new magistrate started into being, combining the offices of supreme justiciary and military dictator.  When Frederick Barbarossa attempted to govern the rebellious Lombard cities in the common interest of the Empire, he established in their midst a foreign judge, called Podesta quasi