[7] In 1757, Najib ad-Dawlah, who was then the governor of Saharanpur under Mughal Empire, invaded the city of Dehradun, with his army of Rohillas, and ruled the area for the next decade.

Many mango groves created during the area still exist today..[8] Ahmad Shah Abdali's invasion of 1757 left Najib in effective control of Delhi who was appointed to the post of Mir Bakhshi.

[citation needed] His brilliant political acumen was used by Ahmad Shah Abdali to isolate Marathas & preventing them from getting even single ally during their conflict with Durrani's power.

Rewarded by this ruler with the charge of a district, now Bijnor, in the North-west corner of Rohilkhand, he had joined the cause of Safdarjung, when that minister occupied the country; but on the latter's disgrace had borne a part in the campaigns of Ghazi-ud-din.

When the Vizier first conceived the project of attacking the government, he sent Najib in the command of a Mughal detachment to occupy the country, about Saharanpur, then known as the Bawani Mahal, which had formed the jagir of the Ex-Vazir Khan Khanan.

He ruled the dwindled Empire for nine years, and died a peaceful death, leaving his charge in an improved and strengthened condition, ready for its lawful monarch.

[citation needed] As the Administrator of Delhi and the imperial heartlands including Agra, Najib ad-Dawlah, was unsuccessful in halting the Jat uprisings led by Raja Suraj Mal.

During one massive assault, the Jats and their leaders overran the Mughal garrison at Agra, plundering the city and looting the two silver gates to the entrance of the famous Taj Mahal in 1764.

[15] After protecting Rohilkhand, Delhi and Agra for nearly ten years as regent of the Mughal Empire, he fell ill and died on 30 October 1770.

When Hafiz Rahmat Khan Barech was killed in battle in April 1774, they were defeated, and Rohilkhand was plundered; and later, the Rohilla power east of the Ganges was ended, and the final treaty by which the territory was incorporated in Awadh was concluded at Lal Dhang.