Seduced by these words and by presents the Polovtsi gave help and aid to the Mongols, gave them victory first, and then led them out to the open country. When towns in the Caucasus foothills and near them were ruined the Mongols turned on the Polovtsi, slew their chief men and numbers of others, took back the bribes to treachery, took every other thing of value and cut down and slaughtered on all sides. The Polovtsi fled and spread terror with their accounts of the Mongols. The whole people left the best pastures and moved toward their northern and western boundaries. Ten thousand families passed into Byzantine regions. John Ducas, the Emperor, took those people then to his service and gave them land in Macedonia and Thrace. Great numbers fled into Russia, which for two centuries had been scourged with their raids and their outrages. Among the fugitives was Kotyan, a Khan whose daughter had married the Galitch prince Mystislav the Gallant. Kotyan implored his son-in-law to help him: “To-day,” said he, “the Mongols have taken our land, they will take yours to-morrow. Assist us; if not we shall be beaten on one day and you the day following.” Mystislav called the Russian princes to a council, at which they resolved to give aid to the Polovtsi. “Unless we help them,” said Mystislav, “they will go with the Mongols and strengthen them.” A deputation went north to ask aid of the princes in Suzdal. Troops were collected and the Russian princes moved against the enemy in confidence. On the way they met Mongol envoys who delivered this message: “We have heard that, convinced by the Polovtsi, ye are marching against us, but we have not come to attack you. We have come against our own horse boys and slaves, the vile Polovtsi; we are not at war with you. If the Polovtsi flee to your country drive them out of it, and seize all their property. They have harmed you, as men tell us; they have harmed us also; that is why we attack them.” The Russian princes gave answer by killing the envoys. Some distance down that great river the Dnieper, a new Mongol embassy met the Russian princes with these words: “If through obedience to the Polovtsi ye have cut down our envoys, and are now bringing war on us, Heaven will judge your action; we have not harmed you.” This time the princes spared the envoys.