Also spelled Sviatoslav, Russian in full Svyatoslav Igorevich (d. 972), grand prince of Kiev from 945 and the greatest of the Varangian princes of early Russo-Ukarinian history.
He was the son of Grand Prince Igor, probably the grandson of Rurik, prince of Novgorod; Svyatoslav was the last the non-Christian rulers of the Kievan state. After coming of age he began a series of bold military expeditions, leaving his mother, Olga, to manage the internal afairs of the Kievan estate until her death in 969.
The "Russian Primary Chronicle" ("Povest vremennykh let") says that Svyatoslav "send\t messengers to the other lands announcing his intention to attack them." Between 963 and 965 he defeated the Khazars along the lower Don RIver and the Ossetes and Circassians in the northern Caucasus; he also attacked the Volga Bulgars. In 967 he defeated the Balkan Bulgars at the behest of the Byzantines, to whom he then refused to cede his conquest. He declared his intention of establishing a Russo-Bulgarian empire with its capital at Pereyaslavets (now Pereyaslav-Khmelnitsky) on the Danube. In 971, however, his comparatively small army was defeated by a Byzantine force under the emperor John I Tzimisces, and Svyatoslav was compelled to abandon his claim to Balkan territory.
In the spring of 972, while Svyatoslav was returning to Kievan Rus with a small retinue, he was ambushed and killed by the Pechenegs (a Turkish people) near the cataracts of the Dnepr (Tne New Encyclopaedia Britannica. 15th ed. Chicago : Encyclopaedia Britannnica, 1992, vol. 11, pg. 427).
He appears to have had at least four sons other than Svyatopolk and Yaroslav (The New Encyclopaedia Britannica, 15th ed., 1992, Chicago : Encyclopaedia Britannica, vol. 12, pg. 823).