ADMINISTRATIONclusions based on them can only be tentative and should take into
account as many other variables as possible.
The first problem lies in the size of the revenues collected in the late
Sasanian period. Qubadh I is said to have raised a total of one hundred
and fifty million dirhams of the weight of a mithqal (Ar.) in taxes from
all sources in the Sawad, which would be equivalent to somewhat
over two hundred and fourteen million dirhams at the ratio of ten to
seven.^94 Apparently the first figure is related to Mawardi's claim that
the land tax base under the unit area system in the Sawad in the sixth
century was one hundred and fifty million jartbs. This would have
been based on the assumption that the above amount only referred to
the land tax in the Sawad and was computed in dirhams, to which
the normal Sasanian tax rate of one dirham per jartb (further assuming
that all land was planted in wheat or barley) was applied to arrive at
the number of jartbs. Mawardi's account then applies the Islamic
system, which he claims is Sasanian, of one dirham and one qa{tz of
grain per jartb (which assumes that all land was planted in wheat) to
produce a land tax alone in the Sawad of two hundred and eighty-
seven million dirhams in the sixth century. The confusion is only
increased by his statement that the tax on each jartb was a dirham
and a qa{tz worth three dirhams of the weight of a mithqal, which
should actually give a total of almost eight hundred million dirhams.^95
A check on this sort of thing is provided by the estimate of four hundred
and twenty million mithqal (six hundred million dirhams) raised by
Khusraw Parviz from all kinds of revenue from his entire empire in
607, the eighteenth year of his reign.^96 Taken at face value, these figures
suggest that the taxes from the Sawad were slightly more than one
third of all Sasanian revenues, and this underscores the economic
importance of this region to the Sasanian state.
The difficulty of using these figures for comparison with the levels
of Muslim revenues is increased by confusion over the area said to
94Ibn l:Iawqal, $urat al-aTl;i, p. 234; Ibn Khurradadhbih, Masiilik, p. 14. Khusraw
Aniishirvan is said to have collected the same amount of taxes in the Sawad in the first
year of his reign (531), see Mas'iidi, Kitiib at-tanbfh wa 'l-ishriif(Beirut, 1965), p. 39.
95 Mawardi, A~kiim as-sultiiniyya, p. 167. According to Ibn Rustah (A'liiq, p. 104),
Qubadh collected 100,550,000 mithqiils of waraq (Ar. "thin") dirhams (equal to
143,642,850 dirhams) in the Sawad.
96 Ibn I:Iawqal, $urat al-ar4, p. 235; Ibn Khurradadhbih, Masiilik, p. 15; Mas'iidi,
Tanbzh, p. 39; Tabarl, Ta'r"ikh, I, 1042. Altheim (Staat, p. 41) and, following him,
Adams (Land Behind Baghdad, p. 71) mistakenly give 240 million dirhams. The claim
that he later collected 600 million mithqiil (over 850 million dirhams) seems suspect
since this is the same number of equivalent dirhams for the first amount of mithqiil.