Sviatoslav I Igorevich (; ; ; ; (943 – 26 March 972), also spelled Svyatoslav, was Grand Prince of Kiev famous for his persistent campaigns in the east and south, which precipitated the collapse of two great powers of Eastern Europe, Khazaria and the First Bulgarian Empire. He conquered numerous East Slavic tribes, defeated the Alans and attacked the Volga Bulgars, and at times was allied with the Pechenegs and Magyars (Hungarians). His decade-long reign over the Kievan 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 in 969 from Kiev (modern-day Ukraine) to Pereyaslavets (identified as the modern village of Nufăru, Romania) on the Danube. In contrast with his mother's conversion to Christianity, Sviatoslav remained a staunch pagan all of his life. Due to his abrupt death in an ambush, his conquests, for the most part, were not consolidated into a functioning empire, while his failure to establish a stable succession led to a fratricidal feud among his three sons, resulting in two of them being killed. Name The Primary Chronicle records Sviatoslav as the first ruler of the Kievan Rus' with a name of Slavic origin, as opposed to his predecessors, whose names had Old Norse forms. Some scholars see the name of Sviatoslav, composed of the Slavic roots for "holy" and "glory", as an artificial derivation combining the names of his predecessors Oleg and Rurik, but modern researchers question the possibility of such a translation of names from one language to another. Sveinald or Sveneld is identical to Sviatoslav, as the Norse rendition of the Slavic name. In 10th-century Eastern Roman Emperor Constantine VII in Greek-language work De Administrando Imperio ("On the Governance of the Empire") records his name as Σφενδοσθλάβος ("Sfendostlabos"). Early life and personality Virtually nothing is known about Sviatoslav's childhood and youth, which he spent reigning in Novgorod. Sviatoslav's father, Igor, was killed by the Drevlians around 945, and his mother, Olga, ruled as regent in Kiev until Sviatoslav reached maturity (ca. 963). Sviatoslav was tutored by a Varangian named Asmud. The tradition of employing Varangian tutors for the sons of ruling princes survived well into the 11th century. Sviatoslav appears to have had little patience for administration. His life was spent with his druzhina