and he was raised by his mother or under her instructions. Her influence, however, did not extend to his religious observance. Sviatoslav had several children, but the origin of his wives is not specified in the chronicle. By his wives, he had Yaropolk and Oleg. By Malusha, a woman of indeterminate origins, Sviatoslav had Vladimir, who would ultimately break with his father's paganism and convert Rus' to Christianity. John Skylitzes reported that Vladimir had a brother named Sfengus; whether this Sfengus was a son of Sviatoslav, a son of Malusha by a prior or subsequent husband, or an unrelated Rus' nobleman is unclear. Children Predslava Oleg of Drelinia (died 977?) Yaropolk I of Kiev (952 - 978) Malusha Vladimir the Great (c. 958 - 1015) Sfengus? Eastern campaigns Shortly after his accession to the throne, Sviatoslav began campaigning to expand Rus' control over the Volga valley and the Pontic steppe region. His greatest success was the conquest of Khazaria, which for centuries had been one of the strongest states of Eastern Europe. The sources are not clear about the roots of the conflict between Khazaria and Rus', so several possibilities have been suggested. The Rus' had an interest in removing the Khazar hold on the Volga trade route because the Khazars collected duties from the goods transported by the Volga. Historians have suggested that the Byzantine Empire may have incited the Rus' against the Khazars, who fell out with the Byzantines after the persecutions of the Jews in the reign of Romanus I Lecapenus. Sviatoslav began by rallying the East Slavic vassal tribes of the Khazars to his cause. Those who would not join him, such as the Vyatichs, were attacked and forced to pay tribute to the Kievan Rus' rather than to the Khazars. According to a legend recorded in the Primary Chronicle, Sviatoslav sent a message to the Vyatich rulers, consisting of a single phrase: "I want to come at you!" (Old East Slavic ) This phrase is used in modern Russian and Ukrainian (usually misquoted as ) to denote an unequivocal declaration of one's intentions. Proceeding by the Oka and Volga rivers, he attacked Volga Bulgaria. He employed Oghuz and Pecheneg mercenaries in this campaign, perhaps to counter the superior cavalry of the Khazars and Bulgars. Sviatoslav destroyed the Khazar city of Sarkel around 965, possibly sacking (but not occupying) the Khazar city of Kerch on the