126 Chapter 7
Lombard attacks on Byzantine Italy, increased activity
among the Slavs on the Danube border, and incursions
by Berber tribesmen against the settlements in North
Africa. Heraclius was an able general—the first em-
peror to take the field in person since the days of
Theodosius—but a war on four fronts was more than
the resources of his empire could bear.
Without adequate manpower in Syria and Pales-
tine, the Byzantines resorted to a mobile defense-in-
depth conducted in part by Arab mercenaries. That is,
they tried to draw the enemy into the interior, disrupt-
ing his communications and defeating his smaller con-
tingents in detail. The size and speed of the Muslim
attack coupled with an almost complete lack of intelli-
gence about Arab intentions rendered this strategy fu-
tile. The Muslims overwhelmed their Byzantine
opponents and then consolidated their victory with
mass conversions in the conquered territories. By 640
they had seized Syria, Palestine, Mesopotamia, and
Egypt, often without encountering significant local
resistance. Many of the empire’s subjects disliked
both its taxes and its insistence upon religious ortho-
doxy and were unprepared to exert themselves in its
defense.
The Sassanid Empire of Persia proved a more diffi-
cult target, but it, too, had been weakened by its long
war with Byzantium. Attacked by several Arab contin-
gents from Mesopotamia, the Persians maintained a
heroic struggle until their last armies were over-
whelmed in 651. In only twenty years, Islam had con-
quered everything from the Nile to Afghanistan.
But the death of the Caliph Omar in 644 marked
the beginning of disputes over who should succeed
him, and for another twenty years the newborn world
of Islam was convulsed by civil wars. The eventual tri-
umph of Mu’awia (ruled 661–680), founder of the Om-
mayad dynasty, led to Islam’s first and greatest schism.
His rival, Muhammad’s son-in-law Ali, was murdered in
661, but his supporters refused to recognize Mu’awia
and became the first Shi’ites. Most of these people were
Persians who may have resented Arab dominance even
after their conversion to Islam. In the centuries to come
they would develop their own system of law; their own
version of the Hadith,or tradition; and a number of ideas
borrowed from Zoroastrian and other sources. Though
a minority among Muslims as a whole, Shi’ites became
the dominant Islamic sect in Iran and what is now Pak-
istan. The majority of western Muslims remained loyal
to the sunnaand are called Sunni Muslims to this day. In
681 a Sunni army marched from Egypt to the Atlantic
Ocean and added North Africa to the house of Islam.
From there, a mixed army of Berbers and Arabs crossed
the Strait of Gibraltar in 711, defeated the Visigothic
king Rodrigo, and by 713 had seized all of Spain with
the exception of its northern coast.
Islam may have been spread by conquest, but it
does not sanction forced conversions. The attractive
qualities of the faith aside, Islamic triumphs in the
Middle East appear to have resulted in part from
anti-Byzantine sentiment among populations long per-
secuted for Monophysite and other heresies and from
the shrewd policy of offering tax breaks and other pre-
ferred treatment to converts. In such areas as Spain and
North Africa the invaders may have seemed less alien
to the Romanized population than their Germanic
rulers. Their faith was different, but the Muslims gener-
ally shared the broader cultural values of the Mediter-
ranean world. Nowhere was an attempt made to
persecute Christians or Jews, the other “peoples of the
book.” Christian and Jewish communities lived peace-
fully within the Islamic world until Muslim intolerance
arose in the twentieth century as a response to Euro-
pean colonialism.Social and Economic Structures in the Islamic World
The Arab warriors who conquered the world from the
Indus to the Pyrenees came from a society that was still
largely tribal in its organization. Lacking governmental
institutions, they retained those of the Byzantines or
Persians, modifying them when necessary to conform
with Islamic law. Roman law was abandoned.
In theory, the caliphs, or successors to the Prophet,
ruled the entire Islamic world as the executors of God’s
law, which they interpreted with the assistance of a
body of religious scholars known as the ulama.The Ab-
basid dynasty, which claimed descent from the Prophet’s
uncle Abbas, displaced the Omayyads in 749 after a bit-
ter struggle and occupied the office with declining ef-
fectiveness until 1538. After the reign of al-Mansu--r from
754 to 775, they made their capital in the magnificent,
newly founded city of Baghdad and administered their
decrees through bureaucratic departments or diwanssu-
pervised by a vizieror prime minister. In practice, local
governors enjoyed the independent powers conferred
by distance. By the middle of the ninth century political
decentralization was far advanced, and by 1200 the
power of the Abbasids had become largely honorific.
The Muslim world was ruled by local dynasties, which
pursued their own policies while nominally acknowl-
edging the authority of the caliph. Spain, which had
never accepted the Abbasids, retained an Omayyad
caliphate of its own. Though the caliph at Baghdad