…he has also attacked the Volga Bulgars.

Sviatoslav’s greatest success is the conquest of Khazaria, the Jewish state between the Volga and the Don, which for centuries has 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 Constantinople may have incited the Rus' against the Khazars, who had fallen out with the Empire after the persecutions of the Jews in the reign of Romanus I Lecapenus.

Sviatoslav began by rallying the Khazars' East Slavic vassal tribes to his cause.

Those who would not join him, such as the Vyatichs, are attacked and forced to pay tribute to the Kievan Rus' rather than the Khazars.

Proceeding by the Oka and Volga rivers, he invades Volga Bulgaria and exacts tribute from the local population, thus bringing under Kievan control the upper Volga River.

He employs Oghuz and Pecheneg mercenaries in this campaign, perhaps to counter the Khazars' and Bulgars' superior cavalry.