THE NATURE OF CONTINUITYvention by the Muslim rulers. In the case of the Jews, this absence of
state support for the religious authority of the exilarch indirectly pro-
vided the conditions enabling the gaons to complete their capture of
the rule of the community through the Rabbinic schools which had,
in fact, started by the sixth century. At the same time the increasing
authority of the rabbinate had provoked a Messianic opposition which
was encouraged by the Islamic conquest and finally ended in the Ka-
raite schism. The conquest was little more than an incident in the
internal development of the Jewish community in Iraq.
The emergence of religious communities was paralleled by the de-
velopment of the poll tax which extended from the sixth until the
early eighth century. By the late Sasanian period, it had become the
contribution which productive noncombatants were required to make
in return for military protection. It acquired its typical Islamic form
in Iraq because there it was paid primarily by the non-Persian, non-
Magian part of the population under the Sasanians. The trend begun
in the Sasanian period continued in the direction of greater regularity,
uniformity and theoretical refinement under the Islamic regime because
Muslims in Iraq were both a ruling religious community and a military
garrison at first. In return for military protection, the economically
productive part of society whose religion differed from that of the
rulers continued to pay the poll tax, but the Muslims elaborated the
exemptions to include everyone too old or too infirm to pay. The
Muslims also added the requirement of possessing a revealed scripture
in order to be eligible to purchase toleration.
The formation of the Islamic community was itself a part of these
developments, and in the seventh century the Muslims in Iraq were
creating the bonds of a religious community in the same way as the
people around them. They brought their own religious law, a form of
congregational worship, and the masjid with them to Iraq, where they
developed vocations of religious leadership, education, and legal
administration which combined their own background with local pat-
terns of organization. Because communal solidarity was usually ex-
pressed in congregational worship, the emergence of the religious com-
munity as a type of socioreligious organization may be symbolized by
the differences between a temple or shrine, the architecture of which
reflects the presence of a deity and the performance of sacrifice, and
buildings designed for congregational worship. The architecture of
churches combined both functions, but the synagogue and masjid were
more completely congregational.