 The three khans of Khalkha in Outer Mongolia had established close ties with the Qing dynasty since the reign of Hong Taiji, but had remained effectively self-governing.While Qing rulers had attempted to achieve control over this region, the Oyirods to the west of Khalkha under the leadership of Galdan were also actively making such attempts.After the end of the war against the Three Feudatories, the Kangxi Emperor was able to turn his attentions to this problem and tried diplomatic negotiations.