Khurshid tried to assert his independence from his vassalage to the Caliphate, supported various rebellions and maintained diplomatic contacts with Tang China.

[1][2][3] According to the traditional account, the Dabuyids had established themselves as the autonomous rulers of Tabaristan in the 640s, during the tumults of the Muslim conquest of Persia and the collapse of the Sassanid Empire.

They owed only the payment tribute and nominal vassalage to the Arab Caliphate, and managed, despite repeated Muslim attempts at invasion, to maintain their autonomy by exploiting the inaccessible terrain of their country.

[1][2] Khurshid succeeded his father at the age of only six, and for eight years the regency was exercised by his uncle Farrukhan-i Kuchak ("Farrukhan the Little").

[1][2][6] The historian Ibn Isfandiyar gives a vivid description of the prosperity of Tabaristan at this time, which was a major centre for textile production (including silk), and which traded with the Turks of Central Asia, probably via the Caspian Sea.

Al-Mansur sent his generals Abu al-Khaṣīb Marzuq and Khazim bin Khuzaymah into Tabaristan, with the intention of completely subduing the country and making it a province.

[1][2] After learning of his family's capture, he is said to have exclaimed "after this there is no inclination to life and joy, and death is the very solace and respite itself", and took poison, probably in 761.

[1][12][13] Tabaristan became a regular province of the Caliphate, ruled from Amul by an Arab governor, although the local dynasties of the Bavandids, Karinids and Zarmihrids, formerly subject to the Dabuyids, continued to control the mountainous interior as tributary vassals of the Abbasid government.

[1][12] After their capture, Khurshid's sons, the crown prince Dadmihr, Hormozd and Vandad-Hormozd, received Arabic names, but otherwise their fate is unknown.