Caliph Al-Ma'mun, showing himself to be a…

Caliph Al-Ma'mun, showing himself to be a judicious sovereign, closely controls his ministers and does not again appoint an all-powerful vizier.

He also tries to maintain strict control over the provincial governors but is forced to allow a relative degree of autonomy to his former general, Tahir, who had been named governor of Khurasan.

He rules independently of Baghdad, not even mentioning the caliph's name in Friday prayers in recognition of caliphal authority.