There are two predominant political factors in Italy which appear at the end of the twelfth century, and hold the field up to the time of Dante’s birth. Out of the war of investitures between Pope and Emperor, the struggle which we associate mainly with the name of Hildebrand (Gregory VII.), emerged the Italian city-states, the free communes of northern and central Italy, whose development culminated in the heroic resistance offered by the first Lombard League to the mightiest of mediaeval German Caesars, Frederick I. (Barbarossa), which won the battle of Legnano (1176) and obtained the peace of Constance (1183). In the south, the Normans--conquering Apulia and Calabria, delivering Sicily from the Saracens--consolidated their rule into a feudal monarchy, making their capital Palermo one of the most splendid cities of the mediaeval world. The third and last of these Norman kings of Sicily, William II. (_Par._ xx. 61-66), died in 1189. The son of Barbarossa, Henry VI., claimed the kingdom in the right of his wife Constance (_Par._ iii. 115-120), and established the Suabian dynasty on the throne. His son, Frederick II., continued the cultured traditions of the Norman kings; but the union in his person of the kingdom of Sicily with the Empire led to a continuous struggle with the Italian communes and the Papacy, which embittered his closing years until his death in 1250. The reign of Frederick II. is the period of the Guelf and Ghibelline factions, and the beginning of the rise of tyrants in the Italian cities, tyrants of whom the most terrible example was Ezzelino da Romano (_Inf._ xii. 110).