TAXESthe authority of the governor of Iraq were those developed in Bahrayn
under Mu'awiya, this figure probably reflects mainly the extension of
crown land in Iraq by reclamation. This means that combined with
the kharaj of the Sawad and the Kuwar Dijla, the total revenues from
lower Iraq under Mu'awiya amounted to somewhat less (allowing for
the estates in Bahrayn) than two hundred and thirty million dirhams.
This also compares favorably with the figure given for Qubadh I in
the Sawad.
There is obviously no basis for claims that the total tax base declined
in lower Iraq in the first century after the conquest because of the
retraction of agriculture. There is, however, some basis for arguing
that the proportion of total revenue was shifting from one kind of
land to another and that the kharaj figures represent a heavier burden
on the land and peasants remaining under that system than had been
the case under the last Sasanians. The kharaj in the Sawad appears to
have remained fairly stable in the first century of Muslim rule. Various
figures of eighteen, forty or one hundred and eighteen million dirhams
are given for al-I:Iajjaj, but under 'Umar II the amount again rose to
Qne hundred and twenty-four million dirhams.10S
Generally speaking, the immediate survival of aspects of the Sa-
sanian taxation system in the early Islamic period was the result of
agreements between Muslim generals and administrators with local
notables to set tribute at the time of the conquest, of the behavior of
notables and peasants who did what they had been used to doing in
the actual division of responsibility for paying taxes, and of the em-
ployment of natives as tax collectors by the time of Mu'awiya. Because
of this kind of institutional inertia, indigenous traditions of agrarian
organization, the computation of the land tax per unit of area, the
taxing of crown lands. by a rent proportional to the yield, the use of
seals to keep track of those who paid, and the three alternative methods
of collection (group responsibility, guarantee by a notable, or direct
collection by revenue agents), were able to survive the conquest. Im-
portant changes also took place, however. These included the increase
in the land and poll tax rates by two to four times the Sasanian level
and the expansion of cultivation in lower Iraq, where the new lands
were not subject to kharaj but were crown land, land grants, or tithe
land.
In taxation, as in administration, one may observe Islamic modifi-
105 BaJadhuri, Futu~, p. 270; Ibn I:lawqal, $urat al-arr;{, p. 234; Ibn Khurradadhbih,
Masiilik, p. 14; Ibn Rustah, A'liiq, p. 105; Mawardi, A~kam as-sultiiniyya, p.169.