THE QUESTION OF CONTINUITYHowever, the tendency has been to lump several hundred years to-
gether and to treat them as a monolithic, static unit. In particular, all
of Late Antiquity from 300 until 600 and Islamic history until about
900 tend to be taken as single periods for the purpose of comparison
and evaluation. But there are really no static "Sasanian" and "Islamic"
models to compare. Proper account should be taken of continuing
change during both periods. Immediate continuities or changes may
only be evaluated by comparing conditions and institutions at the very
end of Sasanian rule with those directly after the Islamic conquest.
Such conditions and changes are described in the accounts of the
conquest and occurred during the lifetime of a single generation. Long-
term continuities or changes resulting from trends and developments
that were taking place from the sixth until the eighth centuries serve
to put the effects of the conquest into perspective.
For the sake of convenience, several shorter periods will be used as
a framework for discussion. The late Sasanian period began with the
political and economic recovery in the early sixth century during the
second reign of Qubadh I (498/9"':'531) and lasted in Iraq until the
Islamic conquest in the 630s. Within this period, the reign of Khusraw
I Aniishirvan (531-79), who completed the reforms of Qubadh I,
contrasts with that of Khusraw II Parviz (591-628), which saw the
most extreme expressions of late Sasanian political absolutism and
imperial ambition. Many of the conditions in Iraq at the time of the
Islamic conquest had only arisen during the reign of Khusraw H. Early
Islamic history is most conveniently subdivided into a period imme-
diately fol1owing the conquest in the 630s until the outbreak of the
first civil war among Muslims in 657, a period between the first (657-
61) and second (680-92) civil wars, and a period following the second
civil war until the end of significant imperial expansion in the second
and third decades of the eighth century. Since the period between the
first and second civil wars virtually coincides with the reign of Mu'awiya
ibn Abi Sufyan (661-80), who was succeeded by his son Yazid (680-
83), it is convenient to call it the Sufyani period. This will serve to
distinguish it and them from the rule of their relatives, the descendents
of Marwan ibn al-J:lakam (684-85), which lasted until the Marwani
dynasty was replaced by the 'Abbasi dynasty in 750. The early Mar-
Want period, when the Islamic empire was at its height, occupies the
decades following the second civil war and the reigns of 'Abd al-Malik
ibn Marwan (685-705) and his son ai-Wand I (705-15). In most