Throughout this period the territorial extent of the realm remained practically unchanged, comprising Sicily, with Malta, and the southern half of the Italian peninsula as far as Terracina on the western coast and the river Tronto on the eastern. There were of course times when the royal authority was disputed within and attacked from without,--feudal revolts, raids by the Pisans, expeditions of the German emperor, diplomatic contests with the Pope,--but it was not permanently limited or shorn of its territories. There were, on the other hand, moments of expansion, particularly by sea, for Sicily was of necessity a naval power and early saw the importance of creating a navy commensurate with its maritime position. The occupation of Tripoli and Tunis by Roger II seized the Mediterranean by the throat; the possession of Corfu threatened the freedom of the Adriatic; but neither conquest was permanent, and in the main the Greek empire and the powers of northern Africa succeeded in keeping the Sicilian kings within their natural boundaries. In area about four-fifths the size of England, the southern kingdom showed far greater diversity, both in the land and in its inhabitants. Stretching from the sub-tropical gardens of Sicily into the heart of the highest Apennines, it was divided by mountain and sea into distinct natural regions between which communication continues difficult even to-day--the isolated valleys of the Abruzzi, the great plain of Apulia, the ‘granite citadel’ of Calabria, the rich fields of Campania, the commercial cities of the Bay of Naples and Gulf of Salerno, the contrasted mountains and shore-lands of Sicily itself. The difficulties of geography were increased by differences of race, religion, and political traditions. The mass of the continental population was, of course, of Italian origin, going back in part to the Samnite shepherds of primitive Italy, and while it had been modified in many places by the Lombard conquest, it retained its Latin speech and was subject to the authority of the Latin church. Calabria, however, was now Greek, in religion as in language, and the Greek element was considerable in the cities of Apulia and flowed over into Sicily, where the chief foreign constituent was African and Mohammedan. Politically, there was a mixed inheritance of Lombard and Roman law, of Greek and Saracen bureaucracy, of municipal independence, and of Norman feudalism, entrenched in the mountain-fortresses of upper Apulia and the Abruzzi; while the diverse origins of the composite state were expressed in the sovereign’s official title, “king of Sicily, of the duchy of Apulia, and of the principality of Capua.” The union of these conflicting elements into a single strong state was the test and the triumph of Norman statesmanship. * * * * *