Sviatoslav I Igorevich (Old East Slavic: С~тославъ / Свѧтославъ Игорєвичь, Sventoslavŭ / Svantoslavŭ Igorevičǐ; , Sviatoslav Igorevich; , Sviatoslav Ihorovych; , Sviatoslav Igaravich; , Svetoslav, , 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.