ADMINISTRATIVE GEOGRAPHYThe unification under Ziyad was incomplete to the extent that Basra
and Kufa remained twin capitals, but this combination was repeated
by 'Ubaydullah ibn Ziyad under Yazid I (680-83) and by Mu~'ab
ibn az-Zubayr during the later years of the second {itna .. The reor-
ganization was only completed in the caliphate of 'Abd al-Malik by
the permanent detachment of Mawsil and the complete unification of
Iraq as a province with Wasit as its capital. This only lasted until the
end of the of the Marwani period,241 however, and under the 'Abbasis
the government of Iraq was divided among local centers.
CONCLUSIONS
On the whole, changes in the administrative structure due to the
conquest were greatest at the upper levels of the hierarchy. The Sa-
sanian Quarter of the West was dismembered and the Sasanian system
of imperial quarters never served as a basis for Islamic administration.
The shape of major configurations in early Islamic administration in
Iraq was determined by accidents of conquest, such as the direction
from which Sasanian provinces were conquered, and the extent of
territory occupied by separate Muslim forces. Although Arbayestan
survived as a unit with its districts, this entire province was attached
to the Jazira. Eventually several districts that had formerly been part
of Byzantine Mesopotamia were included in Arbayestan.
After the Battle of Nihawand in 642, the territory of Kufa and its
dependencies briefly equalled the Sasanian Quarter of the West minus
Arbayestan in its extent. This was the closest the Quarter of the West
came to surviving in Islamic administration. By the end of the seventh
century, Mawsil had been detached from it, and the older province of
Asoristan had been reconstituted in the form of the Islamic province
of Iraq. The territory of Basra and its dependencies combined Maysan
and Khuzistan with much of the Iranian plateau that had been con-
quered by Basran forces, although the distinction between the Sawad
of Basra and that of Kufa may have preserved the former border
between the Sasanian Quarters of the South and the West.
At the other end of the scale, changes in the administrative structure
related to changes in river and canal courses, flooding, and redevel-
Ta'rtkh, Il, 272. Elia bar Shinaye expresses the significance of the unification of Iraq
under Ziyad by calling him the governor of Beth Aramaye; see Elias of Nasibin, Opus
Chronologicum, I, CSCO, Scr. Syri, 21:142, 23:69.
241 Ibn Qutayba, Ma'iiri(, p. 571.