18 ISLAM AT WAR
his son, Siros. Siros made peace with Byzantium and then proceeded to
butcher every conceivable family rival. This practice of destroying rival
siblings would become a regular event during any dynastic change in later
Islamic kingdoms.
Siros’s treachery was not rewarded by any success, for he too fell to an
assassin after an eight-month reign, and the realm fell to pieces. The proud
empire fell into such total chaos that the term “civil war” is hardly appro-
priate. Anarchy is much closer to the truth. Finally, in 632, a king was
found—Yezdegird, a young and inexperienced lad with some royal blood,
but nothing like the experience that would have been required to lead the
ruined Empire back onto its feet.
Had the Byzantine war not ruined Persia, it would have had little dif-
ficulty with the Muslims. At its prime, the Persian army was a formidable
array. The fine Persian cavalry—famous since Alexander’s day—was the
cream of the army. It included not only heavily armored lancers, similar
to later Western knights, but also hordes of lightly armed horse-archers,
including Hun and other steppe tribes as allies. The infantry was not as
well thought of, being mostly peasant levies rudely equipped with bows
or spears. However, when accompanied by Indian elephants, they were a
terrifying opponent to any foe. Under normal circumstances it is unlikely
that the Muslims would have had the strength even to confront the main
Persian armies, but the Sassanian strength had been terribly reduced by
the long war with the Byzantines.
The Persians had created a chain of buffer states to guard their frontier
from the nomadic tribes living in the desert between Iraq and the Arabian
Peninsula. Of these, the chief were the Beni Bekr, whom Khalid encoun-
tered in March of 633. The Beni Bekr had been paid by the Persians to
police their frontier with the wilder tribes to the west, but the financial
drain of the wars had shrunk the subsidy. The result was that Khalid found
a willing ally who was not only familiar with the frontier’s geography and
his enemy’s forces, but also his weaknesses.
Reinforced by his new allies, Khalid moved quickly, and in March 633
he defeated a small Persian force at Kadhima, south of the Euphrates,
close to the Persian Gulf. He then moved through the fringes of the desert
to capture the port city of Ubulla, which surrendered on terms. Crossing
the river, the Arabs found themselves in the rich farmland of the Tigris-
Euphrates basin, which must have seemed a land of plenty to the nomadic
desert warriors. The force actually operated east of the river briefly, but
Khalid, a clever strategist, preferred to keep the desert at his back, not the
river.