Fateh Shah was the king of Garhwal, a small kingdom in North India, from 1684 to 1716.
H. G. Walton states that Fateh Shah led an attack from Dehradun on Saharanpur in 1692. The attack was repelled by Sayyed Ali, the Mughal imperial general. According to research by G.R.C. Williams, Fateh Shah established a township called Fateh Pur in Haraura Pargana of Saharanpur.
According to Rahul Sankrityayan and Fateh Prakash, Raja Fateh Shah also invaded Tibet, where his sword and armour were preserved in the monastery at Daba for a long time.
Dabral and Bhakt Darshan believe that Fateh Shah invaded Sirmur in 1692. Ajay Singh Rawat writes that the year of invasion mentioned by these writers is not correct, and the animosity between Fateh Shah and Raja of Sirmur is the prelude to the Battle of Bhangani (1688). Mat Prakash (or Medni Prakash), the Raja of Sirmur sought the help of Guru Gobind Singh to reconcile his differences with Fateh Shah. The Guru persuaded Fateh Shah to restore good relations with the Raja of Sirmur and to return the seized portion of the Sirmur kingdom.
In 1688, the marriage of Fateh Shah's daughter was arranged with the son of Raja Bhim Chand of Bilaspur (Kahlur). Guru Gobind Singh had sent jewellery worth one lakh rupees to Fateh Shah's daughter at the time of marriage ceremony. However, Bhim Chand had grown wary of the rising influence of Guru Gobind Singh, and had developed animosity toward the Guru. He threatened to cancel the marriage if Fateh Shah accepted the gift from the Guru. Later, the combined forces of Bhim Chand and Fateh Shah launched an attack on Guru Gobind Singh's camp. Guru Gobind Singh was already prepared for a battle, and the two forces met at Bhangani, located about six miles from Paonta, on 18 September 1688.
Dr. Fauja Singh believes that the Battle of Bhangani should not be connected with the story of Fateh Shah's refusal of the wedding presents sent by the Guru. The author of Bichitra Natak doesn't mention the name of Raja Bhim Chand, and states that Fateh Shah fought with him for no obvious reasons. According to Ajay Singh Rawat, one of the possible grievances of Fateh Shah could have been the presence of Guru's armed camp near his territory; Paonta was a strategic location on the only convenient route connecting Nahan (capital of Sirmur) and Garhwal. He also believes that it is likely that the subjects of Garhwal suffered from "lawless activities" of some of the Guru's followers. These reasons could have led him to ally with Bhim Chand to attack the Guru.