Who was this Mughal Emperor that reigned nearly half a century whom Saadat Ali Khan I fought alongside with against the Maratha in the Deccan?
Saadat Ali Khan I:  At the age of 25 he accompanied his father Muhammad Nasir and joined the final campaign of the Mughal Emperor Aurangzeb against the Maratha in the Deccan, where the Mughal Emperor honorably awarded him the title "Khan Bahadur" for his steadfast services. Aurangzeb: Muhi-ud-Din Muhammad (3 November 1618 – 3 March 1707), commonly known by the sobriquet Aurangzeb (Persian: "Ornament of the Throne") or by his regnal title Alamgir (Persian: "Conqueror of the World"), was the sixth, and widely considered the last effective Mughal emperor. Aurangzeb:  His reign lasted for 49 years from 1658 until his death in 1707.
Emperor Aurangzeb