THE NATURE OF CONTINUITYCHANGE
Reinforcement was equally important for effective change. The Arab
Muslim conquerors who came from the peninsula showed a remark-
able resistance to assimilation for at least a generation, and although
this meant a high degree of linear continuity among themselves, it also
changed the situation in Iraq. This involved the introduction of new
tribal influences which were intensified by their association with the
rulers and by the way some aspects of tribal life were sanctioned in
the Qur'an. This meant that the process of detribalization for those
Arabs who settled in the garrison cities was drawn out longer than it
might have been otherwise. It meant the arrival of a new tribal aris-
tocracy, the tribal organization of the army, the persistence of tribal
politics, and the association of tribal traditions of leadership with the
clan of Mul:lammad, which was the starting point for the Shl'a. It
found expression in resistance to intermarriage and in the survival of
bedouin costume in Iraqi cities. It also meant a basic change in the
form of urban organization, assisted by the replacement of the tribal
majlis by the tribal masjid. This produced cities organized around a
central masjid and divided into tribal districts, each with its own tribal
masjid and cemetery. Since masjids were only built where Muslims
settled, no immediate continuity of sacred location occurred, and Mus-
lims tended to avoid local shrines unless there was a Qur'anic sanction.
Muslim vocations of religious leadership also tended to preserve
pre-Islamic professions. The tribal poet found an Islamic form in the
qa$$, the popular preacher and storyteller engaged in exhortation and
in religious education in the masjid. The professional reciter of poetry
(Ar. rawin) became the reciter of the Qur'an (Ar. qarf) and transmitter
of ~adtth. The unofficial arbiter (Ar. ~akam) became the earliest Mus-
lim qacj"i, and the tribal law of retaliation and the practice of arbitration
survived among Muslims because they were sanctioned by the Qur'an.
Because the Islamic community in Iraq was, at first, a garrison, the
conquest had the effect of increasing urbanization, especially among
Arabs, and caused a shift in population to southern Iraq. The conquest
itself removed the Persian population along the southwestern frontier
of Iraq and much of the population in the districts east of the Tigris.
It disrupted the pastoral economy of Iraq and reconcentrated its pop-
ulation in the form of captives, mawalt, and defectors in the new
garrison cities of Basra and Kufa, together with the Arabs from the
peninsula. The Iraqi Arabs who joined the Muslims simply added to