54 | CHAPTER 3
tianity and the birth of Islam, while recognizing first that Christianity was al-
ready a movement with an almost three- century- long history when Constan-
tine became emperor (306), and second that Islam did not begin to reach any
sort of maturation comparable with Christianity’s post- Nicaean (i.e., post-
Constantinian) patristic era until the tenth century. One might also argue,
from a more political perspective, that Constantine’s achievement is hard to
fathom in isolation from earlier Roman imperial history, especially the third
century, while both the Umayyad and the Abbasid phases of the Caliphate
need to be understood in the context of other great ancient empires—notably
Rome and Iran—that preceded Islam in the lands it conquered.
What, then, makes the First Millennium a plausible major periodization?
The short answer is that it provides the best framework in which to respond
to our basic question about Islam’s relation to its historical context “before
and after Muhammad,” especially the Jewish and Christian traditions. At the
beginning of the First Millennium there was no Christianity or rabbinic Ju-
daism; but during the first century these began to form. Long before 1000,
both had matured intellectually and institutionally to the point where one
recognizes in them the doctrines and structures their mainstream adherents
are familiar with today (and their fundamentalists often reject). We can ob-
serve a similar maturation of Greek philosophy in the schools of Alexandria,
as I already noted in passing when discussing the significance of 529; for
Roman law in Justinian’s wide- ranging codification;^14 and we may add two
parallels from the Sasanian Empire. First there was the national Mazdean or
Zoroastrian religion of Iran, whose orally transmitted “scripture,” the Avesta,
was finally turned into hard copy at some point under the Sasanians, proba-
bly in the sixth century, but in a form that apparently embraced a lot of other
material, even of Greek or Indian provenance.^15 Second, as already noted in
chapter 2, there was the new religion preached by the Prophet Mani, who
arose in third- century Mesopotamia and bequeathed his followers a rich
body of doctrine, scripture, and art drawing on Judaism and Christianity,
which they spread both in Iran and beyond, westward into the Roman Em-
pire but also eastward to India and through Central Asia as far as China.
Until the tenth century, Manicheism remained a subtle and adaptable if lim-
ited presence in the Caliphate and a threat to the orthodox, or so they chose
to present it, even if just as a name to tar Muslims of a more liberal cast of
mind.^16
14 Conventional usage places the “classical” phase of Greek philosophy in the fifth to fourth centu-
ries BCE, and of Roman law in the first to second centuries CE, much earlier than the fuller maturations
of which I here speak.
15 S. Shaked, Dualism in transformation (London 1994) 99–119; see below, pp. 201–2.
16 F. de Blois, “Zindīk,” EIs^2 11.510–13.