Using a tactical deception led by Qasar, the Mongols unexpectedly attacked the Kereit at Jej'er Heights. The battle, lasting three days, concluded with a significant victory for Temüjin. Both Toghrul and Senggum were forced into flight; Senggum fled to Tibet, while Toghrul met his end at the hands of a Naiman who failed to recognize him. Temüjin then integrated the Kereit leadership into his ranks, marrying Princess Ibaqa and arranging marriages of her sister Sorghaghtani and niece Doquz to his youngest son, Tolui. The Naiman forces, bolstered by Jamukha and others defeated by the Mongols, prepared for conflict. Informed by Alaqush, ruler of the Ongud tribe, Temüjin faced the Naimans in May 1204 at Chakirmaut in the Altai Mountains, where they suffered a crushing defeat; Tayang Khan was killed, and his son Kuchlug fled westward. The Merkits were substantially weakened later that same year. Jamukha, having left the Naimans during Chakirmaut, was betrayed to Temüjin by his own men, who were then executed for their betrayal. The Secret History mentions that Jamukha requested an honorable execution from his childhood friend, while other sources claim he was dismembered.