Sviatoslav I Igorevich (Old East Slavic: С~тославъ / Свѧтославъ Игорєвичь, Sventoslavŭ / Svantoslavŭ Igorevičǐ; Russian: Святослав Игоревич, Sviatoslav Igorevich; Ukrainian: Святослав Ігорович, Sviatoslav Ihorovych; Bulgarian: Светослав, Svetoslav, Greek: Σφενδοσθλάβος, Sphendosthlabos) (c. 942 – March 972), also spelled Svyatoslav, was a prince of Rus'. The son of Igor of Kiev and Olga, Sviatoslav is famous for his incessant campaigns in the east and south, which precipitated the collapse of two great powers of Eastern Europe—Khazaria and the First Bulgarian Empire; he also conquered numerous East Slavic tribes, defeated the Alans and the Volga Bulgars, and at times was allied with the Pechenegs and Magyars.
His decade-long reign over Rus' was marked by rapid expansion into the Volga River valley, the Pontic steppe and the Balkans. By the end of his short life, Sviatoslav carved out for himself the largest state in Europe, eventually moving his capital from Kiev (modern-day Ukraine) to Pereyaslavets (modern day Romania) on the Danube in 969. In contrast with his mother's conversion to Christianity, Sviatoslav remained a staunch pagan all of his life. Due to his abrupt death in ambush, Sviatoslav's conquests, for the most part, were not consolidated into a functioning empire, while his failure to establish a stable succession led to fratricidal feud among his sons, resulting in two of his three sons being killed. (Read more. . .)