In 1662, J^^ˇasa૪tu Qa૪an of the Right-Wing Qalqa Mongols in Outer Monoglia was murdered by Erinčin Lobsang Tayiǰi, one of his kinsmen who is always referred to as Altyn Tsar in Russian sources. It was an incident that marked the final phase of the Mongol-Oyirad relations going back over four-hundred years. The Oyirad, when they first appeared in history at the beginning of the thirteenth century, were a tribe inhabiting the present-day Tuva in subjection to Činggis Qa૪an. The tribe, however, underwent a considerable change in its ethnic composition by the time it appeared in the seventeenth-century Mongolian and Russian records. History of North Asia after the fall of the Mongol Yüan Empire in 1368 revolved around the Mongol-Oyirad rivalry. What set the Mongols and the Oyirad, both Mongolic-speaking nomadic peoples, apart, then? The Mongols in the narrower sense, that is, those after 1368, comprised the groups that derived themselves from those used to be loyal to the Yüan emperors, while the Oyirad were an anti-Yüan alliance of the tribes who had never been directly subject to them, including the old Oyirad, the Naiman, the Kereyid and the Bar૪ud. This new tribal federation, now known as the Dörben(Four) Oyirad, controlled most of Mongolia for a century after the fall of the Yüan, until the Mongols in the narrower sense were finally brought together to form a federation under Dayan Qa૪an. The Mongols now began a series of conquests of the Oyirad, in the course of which they spread their pastures over the present-day Outer Mongolia, pushing the Oyirad further and further into the Northwestern corner of North Asia. Mongol power was then divided among many tribes. Among them, the Qalqa represented the central force in the Mongol expeditions against the Oyirad, who were driven beyond the Irtysh. From the late sixteenth to the early seventeenth century, the Qalqa Mongols were the overlord of the Oyirad. The Mongol khan who ruled the Oyirad was Ubasi Qong Tayiǰi, grandfather of Erinčin the murderer of his clan-leader J^^ˇasa૪tu Qa૪an. The Russians and the Manchus, in the meanwhile, were moving in on the borders of the Mongols and the Oyirad. The Mongols of Inner Mongolia surrendered to the Manchus in 1634, leaving the Qalqa alone in Outer Mongolia. The only way left for the Qalqa to survive was to form an alliance with their former enemy the Oyirad. Altyn Tsar, who once ruled supreme over the Oyirad, lost his political raison d'etre. In the Oyirad federation, too, the seat of leadership shifted all too rapidly, upsetting tribal balance of power. Under such historical circumstances, Erinčin, the third Altyn Tsar, committed his fratricidal act of 1662.