250 A Short History of The World out the whole Latin world ; if he had little power over men's bodies he held the keys of heaven and hell in their imaginations and could exercise much influence upon their souls. So throughout the middle ages while one prince manoeuvred against another first for equality, then for ascendancy, and at last for the supreme prize, the Pope of Rome, sometimes boldly, sometimes craftily, sometiraes feebly — for the popes were a succession of oldish men and the average reign of a pope was not more than two years — manoeuvred for the submission of all the princes to himself as the ultimate overlord of Christendom. But these antagonisms of prince against prince and of emperor against pope do not by any means exhaust the factors of the European confusion. There was still an Emperor in Constantinople speaking Greek and claiming the allegiance of all Europe. When Charlemagne sought to revive the empire, it was merely the Latin end of the empire he revived. It was natural that a sense of rivalry between Latin Empire and Greek Empire should develop very readily. And still more readily did the rivalry of Greek-speaking Christianity and the newer Latin- speaking version develop. The Pope of Rome claimed to be the successor of St. Peter, the chief of the apostles of Christ, and the head, of the Christian community everywhere. Neither the emperor nor the patriarch in Constantinople were disposed to ac- knowledge this claim. A dispute about a fine point in the doctrine of the Holy Trinity consummated a long series of dissensions in a final rupture in 1054. The Latin church and the Greek church became and remained thereafter distinct and frankly antagonistic. This antagonism must be added to the others in our estimate of the con- flicts that wasted Latin Christendom in the middle ages. Upon this divided world of Christendom rained the blows of three sets of antagonists. About the Baltic and North Seas remained a series of Nordic tribes who were only very slowly and reluctantly Christianized ; these were the Northmen. They had taken to the sea and piracy, and were raiding all the Christian coasts down to Spain. They had pushed up the Russian rivers to the desolate central lands and brought their shipping over into the south-flowing rivers. They had come out upon the Caspian and Black Seas as pirates also. They set up principalities in Russia ; they were the first people to be called Russians. These Northmen Russians came near to taking Constantinople. England in the early ninth century was a Christianized Low German country under a king, Egbert, a protege and pupil of Charlemagne. The Northmen wrested half
