785 Rebellion of Mahdi’s eldest son, Musa, because Harun is preferred as heir. Death of Mahdi on his way to crush the rebellion. Musa, who takes the title Hadi, succeeds. Rising of Hosein b. Ali suppressed.
786 Hadi attempts to exclude Harun from the caliphate, and is smothered at instigation of his mother. Harun ar-Rashid, the most celebrated of the caliphs, succeeds without opposition.
789 The Arabs invade Rumania.
792-793 Suppression of the party formed by Yahya b. Abdallah.
797-798 Continued victories over the Byzantines cause the empress Irene to sue for peace. The Khazars driven out of Armenia.
800 The Aglabite dynasty founded at Kairwan.
801 Harun sends an embassy to Charlemagne.
802 The emperor Nicephorus refuses to continue payment of tribute. Harun makes such a devastating invasion of Asia Minor that Nicephorus sues for peace. He breaks it the next year, and the same process is repeated.
804-805 Rebellion in Khorasan.
806 Peace renewed with Nicephorus after hostilities have once more been begun.