Jaswant Singh succeeded his father on his death by special decree of the Emperor
Shah Jahan, in accordance with his father's wishes, on 6 May 1638. He was invested by Imperial authority and inherited the parganas of
Jodhpur,
Siwana,
Merta,
Sojat,
Phalodi and
Pokharan (Satalmer) in
jagir. He was installed on the gaddi at Sringar Chowki,
Mehrangarh, Jodhpur, on 25 May 1638. He was granted the personal title of Maharaja by the Emperor Shah
Jahan, on 6 January 1654. Jaswant Singh's ascension to the throne had an instrumental role of his father's favourite concubine,
Anara Begum, who used to regard Jaswant as her own son and also had differences with the heir-apparent
Amar Singh Rathore, who was later granted the territory of
Nagore as compensation. == Battle of Dharmat==