Khurasan was the base for early recruitment of Abbasid armies, especially the Abbasid takeover received support from Arab settlers aiming to undermine the important sections of non-Muslim aristocracy. The Abbasids succeeded in integrating Khorasan and the East into the central Islamic lands. The state was gradually Persianized through political influence and financial support of the dihqans. Al-Ma'mun emerged as the victor in the Fourth Fitna with the help of Khorasani forces and appointed Tahir ibn Husayn as the governor. Later, he appointed Talha as the governor in 822 and Abdallah in 828. But after the Abbasid decline, Khorasan ended up turning into a virtually independent state under a Persian mawla who rose to favour under Al-Ma'mun.
Khurasan was the base for early recruitment of Abbasid armies especially the Abbasid takeover received support from Arab settlers aiming to undermine the important sections of non-Muslim aristocracy. The Abbasids succeeded in integrating Khorasan and the East into the central Islamic lands. The state was gradually Persianized through political influence and financial support of the dihqans. Al-Ma'mun emerged as the victor in the Fourth Fitna with the help of Khorasani forces and appointed Tahir ibn Husayn as the governor Later, he appointed Talha as the governor in 822 and Abdallah in 828 But after the Abbasid decline, Khorasan ended up turning into a virtually independent state under a Persian mawla who rose to favour under Al-Ma'mun.