The Bulgarian Empire was large, and had played an important part in the past. It had a Tsar, while Russia had only a Grand Prince, and, although now declining in strength, was a troublesome neighbor to the Greek Empire. The oft-repeated mistake of inviting the aid of another people was committed. Nothing could have better pleased Sviatoslaf than to assist the Greek Empire, and when he captured the Bulgarian capital city on the Danube, and even talked of making it his own capital instead of Kief, it looked as if a great Slav Empire was forming with its center almost within sight of Constantinople. The Greeks were dismayed. With the Russians in the Balkan Peninsula, the center of their dominions upon the Danube--with the Scythian hordes in the South ready to do their bidding--and with scattered Slavonic tribes from Macedon to the Peloponnesos gravitating toward them, what might they not do? No more serious danger had ever threatened the Empire of the East. They rushed to rescue Bulgaria from the very enemy they had invited to overthrow it. After a prolonged struggle, and in spite of the wild courage displayed by Sviatoslaf, he was driven back, and compelled to swear by Perun and Volos never again to invade Bulgaria. If they broke their vows, might they become "as yellow as gold, and perish by their own arms." But this was for Sviatoslaf the last invasion of any land. The avenging Pechenegs were waiting in ambush for his return. They cut off his head and presented his skull to their Prince as a drinking cup (972). It seems scarcely necessary to call attention to the fact that the transforming energy in this early period of Russian history was not in the native people; but that the Slav, in the hands of his Norse rulers, was as clay in the hands of the potter. In the treaty of peace signed at Kief (945) by the victorious Igor, of the fifty names recorded by Nestor only three were Slavonic and the rest Scandinavian. There can be no doubt which was the dominant race in this the heroic age of Russia. So we have seen a weaker people submitting to the rule of a stronger, not by conquest, like Spain under the Visigoths; not overrun and overridden as Britain by the Angles and Saxons and Gaul by the Franks; but, in recognition of its own helplessness, voluntarily becoming subject to the control of strangers. And we see at the same time the brilliant, restless Norseman, with no plan of establishing a racial dominion, but simply in the temporary enjoyment of his own warlike and robber instincts, engrafting himself upon a less gifted people, and then adopting its language and customs, letting himself be absorbed into the nationality he has helped to create, and becoming a Russian, with the same facility as Rollo and his sons at the very same period were becoming Frenchmen. CHAPTER IV RUSSIANS CONVERSION--GREEK AND LATIN CHRISTIANITY