ملخص الجهاز:
During the progress of this rebellion, a Shi'a movement• more formidable in its aims and objects and fraught with more serious consequences to the 'Abbasid Caliphate=-was started by ·one of the votaries of the Isrna'Ili sect, named 'Abd Allah b.
Mawardi, there are ten duties to be per• formed by a Caliph : ( 1) To uphold the fundamental principles of the Muslim religion; ( 2) To decide law-suits and to settle disputes; (3) To defend Muslim territories; (4) To ad• minister the penal law; (5) To guard the frontiers by keeping garrisons and making preparations for war; ( 6) To fight those who refuse to accept Islam or to submit upon terms laid down for non-Muslims; ( 7) To levy taxes and imposts according to law; ( 8) To pay the annuity from the State treasury; ( g) To appoint trustworthy men and councillors for the administration of different districts and for fiscal purposes; and (Io) Personally to inspect and control the administration.
After Mamun's accession to the throne in 198/813, Tahir was appointed the Governor of Al-jazirah and financial administrator of the Sawad with the position of Military Commander at Baghdad," and his son 'Abd Allah was entrusted with the duty of pacifying the western parts of the Empire.
At the time of the appointment of Tal. Qa in 207/822 to the government of Khurasan, the chief of Ushrusana, Kawus who had consented to pay tribute to Maroun, revolted against the authority of the Caliphate; consequently a force was sent from Baghdad under the com• mand of Ahmad b.
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