CONCLUSIONthe tribal nature of these new cities; but the Persians found themselves
integrated into the tribal system either as allies, such as the If.amrii'
and Asiiwira, or as mawiilz. This demographic change in southern Iraq
meant an increase in agriculture at the expense of pastoralism. But
the only important changes in the tribal distribution in Iraq during
the seventh century were the permanent displacement of the tribes of
Namir and Taghlib north of the Euphrates and the movement of
pastoral Arabs across the Tigris in upper Iraq towards the end of the
century. However, the consequences of the flooding and plague in 628,
along with the conquest, also contributed to demographic and eco-
nomic changes.
Because the conquest replaced Magian rulers with Muslims, it also
removed the friction between Magians and Jews and Christians over
inhumation, bathing, and ablutions. Islam actually gave a positive
sanction to these practices with the result that the public bath became
a part of Islamic society. By the same token, the conquest removed
the difficulties of conversion from Magianism to Christianity.
The conquest also had the effect of suppressing the hierarchic so-
ciety, ranking system, and administrative organization and practice of
'the late Sasanian period at the upper levels. With the sole exception
of the ~iijib, the hierarchic structure of the royal court disappeared
along with the clothing code. To the extent that the conquest brought
a breakdown of the late Sasanian centralization, it restored some as-
pects of the situation prior to the Sasanian reorganization in the sixth
century. The organizational arrangements originally brought about
for practical reasons were only gradually coordinated with the main
outlines of the Sasanian administrative system, with important revivals
under Mu'awiya and the early Marwanis. Ultimately the old province
of Beth Aramaye reappeared as the Islamic province of Iraq.
Thus, there is an element of continuity in some of the changes
introduced by the conquest. Although the defensive frontier in Iraq
was shifted from the southwest to the north and northeast toward
Iran, and the new provincial capitals founded by the Muslims at Basra,
Kufa, Mawsil, and Wasit were all situated with the Tigris or Euphrates
rivers between them and Iran, they were also placed close to previous
Sasanian administrative centers. Kufa was about three miles from Hira;
Basra was across from perath; Mawsil was across from Nineveh; and
Wasit was across from Kaskar.
Although at first, Arabs did not adopt the principle behind the
clothing code for themselves, with the possible exception of the lim-