During the 1630s Tibet was deeply entangled in rivalry, evolving power struggles and conflicts, not only between the Tibetan religious sects but also between the rising Manchus and the various rival Mongol and Oirat factions, who were also vying for supremacy amongst themselves and on behalf of the religious sects they patronised. For example, Ligdan Khan of the Chahars, a Mongol subgroup who supported the Tsang Karmapas, after retreating from advancing Manchu armies headed for Kokonor intending destroy the Gelug. He died on the way, in 1634 but his vassal Choghtu Khong Tayiji, continued to advance against the Gelugpas, even having his own son Arslan killed after Arslan changed sides, submitted to the Dalai Lama and become a Gelugpa monk. By the mid-1630s, thanks again to the efforts of Sonam Rabten, the 5th Dalai Lama had found a powerful new patron in Güshi Khan of the Khoshut Mongols, a subgroup of the Dzungars, who had recently migrated to the Kokonor area from Dzungaria. He attacked Choghtu Khong Tayiji at Kokonor in 1637 and defeated and killed him, thus eliminating the Tsangpa and the Karmapa's main Mongol patron and protector.