In the eleventh century, as in the early nineteenth, Italy was merely a geographical expression. The unity of law and government which it had enjoyed under the Romans had been long since broken by the Lombard invasion and the Frankish conquest, which drew the centre and north of the peninsula into the currents of western politics, while the south continued to look upon Constantinople as its capital and Sicily passed under the dominion of the Prophet and the Fatimite caliphs of Cairo. Separated from the rest of Italy by the lofty barrier of the Abruzzi and the wedge of territory which the Papacy had driven through the lines of communication to the west, the southern half followed a different course of historical development from the days of the Lombards to those of Garibaldi. Nature had thrust it into the central place in the Mediterranean world, to which the gulfs and bays of its long coast-line opened the rich hinterland of Campania and Apulia and the natural highways beyond. Here had sprung up those cities of Magna Graæcia which were the cradle of Italian civilization; here the Romans had their chief harbors at Pozzuoli and Brindisi and their great naval base at Cape Miseno; here the ports of Gaeta, Naples, Amalfi, and Bari kept intercourse with the East open during the Middle Ages. And if the genius of Hamilcar and Hannibal had once sought to tear the south and its islands from Italy to unite them with a Carthaginian empire, their close relations with Africa had again been asserted by the raids and conquests of the Saracens, while their connection with the East made them the last stronghold of Byzantine power beyond the Adriatic. In the long run, however, it has been pointed out that, if the culture of this region came from the south, its masters have come from the north;[62] and its new masters of the eleventh century were to unify and consolidate it at the very time when the rest of the peninsula was breaking up into warring communes and principalities. In the year 1000 the unity of the south was largely formal. The Eastern Empire still claimed authority, but the northern region was entirely independent under the Lombard princes of Capua, Benevento, and Salerno, while the maritime republics of Naples, Gaeta, and Amalfi owed at best only a nominal subjection. The effective power of Byzantium was limited to the extreme south, where its governors and tax-collectors ruled in both Apulia and Calabria. Of the two districts Calabria, now the toe of the boot, was the more Greek, in religion and language as well as in political allegiance, but its scattered cities were unable to defend themselves against a vigorous attack. The large Lombard population of Apulia retained its speech and its law and showed no attachment to its Greek rulers, whose exactions in taxes and military service brought neither peace and security within nor protection from the raids of the Saracens. There was abundant material for a revolt, and the Normans