Fourth Fitna

This article records tradition as it has been passed down and reported. Its sources are not yet part of the atlas's verified catalogue.

The Fourth Fitna was a civil war between the sons of the Abbasid caliph Harun al-Rashid over succession to the caliphate following his own death in 809. Harun had divided the empire's administration between his two sons during his own lifetime, naming al-Amin caliph in Baghdad while granting al-Ma'mun a wide autonomous governorship over Khurasan in the east, an arrangement that collapsed into open war once al-Amin attempted to name his own son heir instead of honoring al-Ma'mun's own already established succession rights.

Al-Ma'mun's general Tahir ibn Husayn led a prolonged campaign westward from Khurasan, culminating in a year long siege of Baghdad itself. The city fell to Tahir's forces in September 813 after a devastating siege that badly damaged much of Baghdad, and al-Amin himself was captured and executed, leaving al-Ma'mun as sole caliph over an empire his own family's war had left visibly weakened and materially damaged. Baghdad itself, built only a few decades earlier as the Abbasid dynasty's own showcase capital, bore the physical cost of the siege directly, and observers at the time described a city whose grandest quarters had been reduced to ruin by the very civil war fought to decide who would rule it.

This article records tradition as it has been passed down and reported. Its sources are not yet part of the atlas's verified catalogue.

The Fourth Fitna was framed by contemporaries chiefly as a dynastic succession dispute rather than a doctrinal one, a rivalry between two brothers over an inheritance their own father had divided between them rather than a war fought over any single point of religious belief itself. Yet the war's aftermath carried a real and lasting religious consequence that its immediate causes had not predicted at the outset of the fighting.

Al-Ma'mun's later reign became strongly associated with state support for Mu'tazilite theology and the mihna inquisition that followed from it, a religious policy shift historians trace in part to the coalition of eastern, Persian-influenced supporters who had backed his own cause during this civil war against his brother al-Amin. The war also left the Abbasid caliphate's core territories visibly damaged, and some historians trace the caliphate's later reliance on Turkic military slaves directly to the weakened Arab military factions this civil war left behind it after Baghdad's own devastating siege. The Fourth Fitna therefore stands, in the historical record, as a war whose stated cause was a narrow family inheritance dispute but whose consequences reached into the caliphate's own religious policy and military composition for generations afterward.