The decline of the feudal system was due mainly to the increasing power of the Crown on the one hand, and of the lower ranks on the other; more especially from the extension of the privileges of towns. But the feudal principle itself was weakened by the tendency to commute military service for money, enabling the Crown to employ paid troops. _II.--Italy and Spain_ After the disruption of Charlemagne's empire the imperial title was revived from the German, Otto the Great of Saxony. His imperial supremacy was recognised in Italy; the German king was the Roman emperor. Italian unity had gone to pieces, but the German supremacy offended Italy. Still from the time of Conrad of Franconia the election of the King of Germany was assumed, at least my him, to convey the sovereignty of Italy. In the eleventh century Norman adventurers made themselves masters of Sicily and Southern Italy. In Northern Italy on the other hand the emperors favoured the development of free cities, owning only the imperial sovereignty and tending to self-government on Republican lines. The appearance on the scene in the twelfth century of the Emperor Frederick Barbarossa introduced a period characterised by a three-fold change: the victorious struggle of the northern cities for independence; the establishment of the temporal sovereignty of the Papacy in the middle provinces; and the union of the kingdom of Naples to the dominions of the Imperial House. The first quarrels with Milan led to the formation of the Lombard league, and a long war in which the battle of Legnano gave the confederates a decisive victory. The mutual rivalries of the States, however, prevented them from turning this to good account. Barbarossa's grandson, Frederick II., was a child of four when he succeeded to the Swabian inheritance, and through his mother to that of Sicily. It was now that the powerful Pope Innocent III. so greatly extended the temporal power of the Papacy, and that the rival parties of Guelfs and Ghibelins, adherents the one of the Papacy, the other of the Empire, were established as factions in practically every Italian city. When the young Frederick grew up he was drawn into a long struggle with the Papacy which ended in the overthrow of the Imperial authority. From this time the quarrel of Guelfs and Ghibelins for the most part became mere family feuds resting on no principles. Charles of Anjou was adopted as Papal champion; the republics of the North were in effect controlled by despots for a brief moment. Rome revived her republicanism under the leadership of Rienzi. In the general chaos the principle interest attaches to the peculiar but highly complicated form of democracy developed in Florence, where the old Patrician families were virtually disfranchised. Wild and disorderly as was the state of Florence, the records certainly point to the conditions having been far worse in the cities ruled by the Visconti and their like.