56 • 5 THE EARLY ARAB CONQUESTS
control over Syria. Another dust storm helped the Arabs to defeat
the Persians in 637 at Qadisiya and hence to overrun Iraq.- Contrary to their image in popular histories, not all Arab warriors
were fired up with Muslim zeal. A few were, but others belonged to
Christian tribes estranged from the Byzantine Empire. Being
Christian did not bar an Arab from fighting for the caliphate. Some
Muslim leaders and tribes may have believed in predestination and
martyrdom as their passport to paradise. Most tribal Arabs be¬
lieved in looting. Economic hardship in Arabia had brought many
of them to the verge of starvation. In fact, the Arab conquests facil¬
itated a Semitic emigration from Arabia comparable to those of the
earlier Akkadians and the Arameans, for the Arabian Peninsula of¬
ten became overpopulated. - Years of warfare between the Sasanid and Byzantine empires had
depleted the resources and manpower of both. Up to about 620,
the Sasanid Persians had seemed to be taking over the whole Mid¬
dle East. Then the Byzantine emperor Heraclius managed to reor¬
ganize his forces to push the Sasanids back to Iraq and Persia. Each
side hired mercenaries, mainly Arabs; but as the Byzantines could
no longer afford to pay the Ghassanid tribe (see Map 2.1 in Chap¬
ter 2), southern Palestine was opened to Muslim penetration even
in Muhammad's last years. The Persians, however, thought they
were rich enough to do without their Lakhmid vassals. As a result,
the pro-Byzantine and pro-Sasanid Arabs had both become unreli¬
able by 632, and some converted to Islam. - The subject peoples, especially those under Byzantine rule in Syria
and Egypt, were discontented. Although they had cultural and eco¬
nomic grievances, the open issue was theological or, rather, Christo-
logical. The Byzantine Empire held the Orthodox (or Chalcedonian)
view, explained in Chapter 2, that Jesus Christ combined in his per¬
son both a divine and a human nature. The Egyptian Copts and
their Syrian counterparts, the Jacobites, believed in his single and
wholly divine nature, according to the Monophysite doctrine. Em¬
peror Heraclius, anxious to win their support, proposed a compro¬
mise: Christ contained two natures within one will. Almost no one
(except the Maronites of Lebanon, whom we discuss later) liked that
solution. The disgruntled Syrian and Egyptian Christians viewed the
Muslim Arabs as liberators from the Byzantine yoke and often wel¬
comed them. The Copts, for example, turned Egypt over in 640 to
Amr's Arab force, which, even with reinforcements, numbered fewer