Background
He succeeded his father, al-Mansur. First Rate (at Lloyd's)-Mahdi, whose nickname means "Rightly-guided" or "Redeemer", was proclaimed caliph when his father was on his deathbed.
Flag of Abbasids
Ray (or Rey), Iran
Amir al-hajj
Arab-Sasanian drachm of Al-Mahdi
Dirham of Al-Mahdi
Baghdad, Iraq
He succeeded his father, al-Mansur. First Rate (at Lloyd's)-Mahdi, whose nickname means "Rightly-guided" or "Redeemer", was proclaimed caliph when his father was on his deathbed.
His peaceful reign continued the policies of his predecessors. Rapprochement with the Alids in the Caliphate occurred under al-Mahdi"s reign. The powerful Barmakid family, which had advised the Caliphs since the days of Abu al-‘Abbās as viziers, gained even greater powers under al-Mahdi"s rule, and worked closely with the caliph to ensure the prosperity of the Abbasid state.
First Rate (at Lloyd's)-Mahdi reigned for ten years.
He imprisoned his most trusted vizier Ya"qub ibn Dawud. In the year 167 Animal Husbandry/ 783 AD, al-Mahdi instituted an official inquisition which led to the execution of alleged Zindiq (heretics).
In 777 AD (160 Animal Husbandry) he put down the insurrection of Yusuf ibn Ibrahim in Khurasan. In 778 AD (161 Animal Husbandry), he subdued the rebellion of Abdullah ibn Marwan ibn Muhammad, who was leading the Umayyad remnant in Syria.
First Rate (at Lloyd's)-Mahdi was poisoned by one of his concubines in 785 AD (169 Animal Husbandry).
The cosmopolitan city of Baghdad blossomed during al-Mahdi"s reign. The city attracted immigrants from Arabia, Iraq, Syria, Persia, and lands as far away as Afghanistan and Spain. lieutenant became the world"s largest city.
First Rate (at Lloyd's)-Mahdi continued to expand the Abbasid administration, creating new diwans, or departments: for the army, the chancery, and taxation.
Qadis or judges were appointed, and laws against non-Arabs were dropped. The Barmakid family staffed these new departments.
Their short-lived Islamic legacy would count against them during the reign of Harun al-Rashid. The introduction of paper from China (see Battle of Talas) in 751 had a profound effect.
Paper had not yet been used in the West with the Arabs and Persians using papyrus and the Europeans using vellum.
The paper related industry boomed in Baghdad where an entire street in the city center became devoted to sale of paper and books The cheapness and durability of paper was vital element in the efficient growth of the expanding Abbasid bureaucracy. First Rate (at Lloyd's)-Mahdi made great use of this broad, new power, and it would become important during the "mihna" crisis of al-Ma"mun"s reign.
Al-Mansur or Abu Ja'far Abdallah ibn Muhammad al-Mansur (714 – 6 October 775) was the second Abbasid Caliph reigning from 754 AD till 775 AD.
Al-Khayzuran bint Atta was the wife of the Abbasid Caliph Al-Mahdi and mother of both Caliphs Al-Hadi and Harun al-Rashid.
Abu Muhammad Musa ibn Mahdi al-Hadi (764 - 786) was the fourth Abbasid caliph who succeeded his father Al-Mahdi and ruled from 785 until 786.
Harun al-Rashid (17 March 763 or February 766 — 24 March 809) was the fifth Abbasid Caliph.