Baghdad; Round City and section through gate - Abbasid, Iraq

Baghdad, of course remains the most famous memorial to the Abbasids, 

although nothing remains of the fortified Round City built for the Caliph

 Mansur (754 - 775).  Its purpose was to serve as an administrative capital, 

a Caliphal palace, and a place to settle thousands of Khurasani-Arab troops.  

The location of Baghdad was also particularly good for communications.  

Militarily it housed a large army at the center of the state; these forces 

included regular troops, the Caliph's own guard, the city's shurta police 

and haras internal security force, as well as Baghdad's own paramilitary 

militia.  The great majority of the population, which may have reached 

as many as a half-million by the year 800, lived in sprawlingsuburbs 

around the Round City, some of which had been built by Khurasani 

military chiefs to house their own followers.

Reference:

D. Niccole and Angus McBride(illus.), "Armies of the Muslim Conquest," Men-At-Arms 225, Osprey Pub., 1993, Pages 23-24.

Respectfully Submitted;

Marcus Audens