Do you have a list of generals? And they may have been fired because the war was not won.
The Abbasid Dynasty founded Baghdad around the year 762. The decision to relocate the Islamic capital from Damascus (the capital of the prior Umayyads Dynasty) came after the Abbasid rulers usurped regional power from their predecessors and thus sought to relocate power to a distant area. Baghdad would eventually become a flourishing city during the Abbasid period until the infamous Sacking of Baghdad by the Mongols in 1258.
AHA THE WASHINGTON POST... VERY CLASSY It may be a reflection on human nature, that such devices should be necessary to control the abuses of government. But what is government itself, but the greatest of all reflections on human nature? If men were angels, no government would be necessary. If angels were to govern men, neither external nor internal controls on government would be necessary.