This vengeful widow next attacked Korosten. Unable to take it by force, she destroyed it by cunning. She sent a message to the inhabitants saying: “You have neither mead nor skins in abundance; give me a tribute of three pigeons, and as many sparrows from each house, and I will leave you in peace.” The Drevlians, pleased with this moderation, sent the birds at once. When evening came, Olga had rags steeped in oil tied to their wings and ignited. The terrified creatures, set free, flew to their cots and nests, and soon every house in Korosten was in flames. The inhabitants, rushing out of the place, were either killed or captured. This was a victory of far-reaching importance, for had Olga failed to conquer the Drevlians, other tribes would have revolted, and Kief would have been lost. Olga ruled wisely and firmly till 957, when Sviatoslav, her only son, reached manhood and succeeded his father; then she made a journey to Tsargrad, became a Christian and was baptized under the name of Helen, the Greek Emperor being her godfather. It is said that upon her return she strove to introduce Christianity into Russia, but was unsuccessful, mainly because of her son’s opposition. She, however, remained a strong advocate of the new faith and has been canonized by the Church, as the first Russian who ascended to the heavenly kingdom. Sviatoslav, whose sole delight was in war, began his stormy rule by marching against the only Slavs east of the Dnieper, who paid him no tribute, the tribe of the Vyatichi. They were at that time tributary to the Kazars, a tribe that had issued from Northern Asia and were known to the Armenian historians as early as the second century. In the ninth century they were familiar to the Byzantines as the Eastern Turks; by the eighth century they had gained the greater part of Tauris, the present Crimea. It is not known when they first met the Slavs, but in the middle of the ninth century four Slav tribes paid tribute to the Kazars. The Kazan state itself was a composite one with four religious systems, Paganism, Mohammedanism, Judaism and Christianity. The Khan was converted to Judaism in the eighth century, and in a letter written by Khan Joseph to a Rabbi in Bagdad, he claimed to be ruler over nine nations of the Caucasus and thirteen near the Black Sea. Sviatoslav attacked Sarkel on the Don, the chief western town and fortress of the Kazars, and captured it. Then he marched eastward to the Volga, and sailed down the river to Itil, the Kazar capital, near the northern shore of the Caspian. Itil, and all the towns of that region, were seized and plundered. Next the Russian prince marched to the foot of the Caucasus, and turned westward toward the Azoff, or “Sea Bend,” as the Russians call it. He overcame all forces that met him on the way, and established Tmutarakan, with its capital at the Greek town Tamatarche, between the Azoff and the Euxine.