Along with his brother Humayd, Hasan was active in the Abbasid cause in Khurasan during the years before the Revolution, serving as a deputy naqib.
This measure was vehemently opposed by the Arab settlers of Khurasan, but according to Khalid Yahya Blankinship "it may have helped to discourage the Turks for a couple of years by keeping the Transoxianans on the Muslims' side".
Faced with this crisis, the Caliph Hisham ibn Abd al-Malik (r. 723–743) took drastic measures: Khurasan was separated from the purview of the governor of Iraq and raised to a separate province, under the Jaziran general Ashras ibn Abdallah al-Sulami.
He was obliged to negotiate the borders of his state with Abu Sa'id Mirza and after negotiations Jahan Shah decided to return territorial demarcation to Shahrukh Mirza's times (Jahan Shah keeping Iraq-i-Ajam while Abu Sa'id keeping Khurasan).
Its numerical decline in Khurasan meant that the Khurasan-born Arabs could no longer be completely controlled by force; this opened the way for the appointment of a native Khurasani Arab governor, Nasr ibn Sayyar, to succeed Asad, and, eventually, for the outbreak of the Abbasid Revolution that toppled the Umayyad regime.
Early Islamic usage regarded the area east of western Persia (Jibal, also known as Persian Iraq) as part of the poorly-defined region of Khurasan, extending to the Indus River and Sindh.
In almost all the Iranian provinces, according to Al Masudi, fire temples were to be found – the Madjus he says, venerate many fire temples in Iraq, Fars, Kirman, Sistan, Khurasan, Tabaristan, al Djibal, Azerbaijan and Arran.
The Khurasanid dynasty was founded by Abd al-Haqq ibn Abd al-Aziz ibn Khurasan, who was appointed as governor of Tunis by the Hammadids, after they were solicited by its inhabitants who complained about the Zirid sultan Al-Mu'izz ibn Badis, who didn't protect them from Hilalian attacks.
After the suppression of the revolt of Abdallah ibn Ali against Caliph al-Mansur (r. 754–775) in Syria in 754, the long-simmering tension between Abu Muslim—who had come to rule Khurasan as a near-sovereign prince, practically independent of the Abbasid family—and al-Mansur came to the fore.
Abu 'Ali then fled to the Buyids, and received a grant from the Caliph Al-Muti for control of Khurasan.