THE EXPANSION OF CHRISTENDOM AND THE CRUSADES
WHILE feudal lords were busily engaged in acquiring power over various localities and the popes aimed at world- empire, there was one work in which they cordially coöperated; namely, the expansion of Christendom and the crusades. The Christian world in the West of Charlemagne's time had covered a very restricted area, which the invasions of Northmen, Saracens, and Hungarians during the break-up of his empire had threatened to reduce further. But these new invaders had been finally checked or absorbed. The Northmen had been converted even in their home land, Scandinavia, and the Magyars accepted Christianity during the reign of St. Stephen of Hungary ( 997-1038). At the same time there were political divisions rife in the Mohammedan world, and there was a temporary lull in the pressure which the nomads of Asia had been exerting upon the West almost continuously since the first appearance of the Huns. Finally, in western Europe the population was now increasing instead of declining as in the time of the Roman Empire. The supply of land to give out as fiefs was becoming exhausted and younger sons and other would-be vassals must migrate elsewhere to satisfy their desires. Also the villas were overcrowded with tenants and serfs, many of whom could readily be drawn away by an offer of new lands and slightly better conditions of holding.
The causes of expansion
Into southern Italy, where Byzantines and Saracens and local nobles and towns were contending, came in the early eleventh century Norman pilgrims returning from Jerusalem and Norman soldiers of fortune still possessed by their race's old spirit of wandering and adventure. After serving the contending parties for a time as mercenaries, they entered the fray in their
Normans in southern Italy and Sicily