"كتيّب سوريا (بما في ذلك فلسطين). لندن: إدارة استخبارات الأركان البحرية، يونيو ١٩١٩" [ظ‎‎٦‎٦] (٧٣٨/١٣٧)

126
MILITARY HISTORY
The Arab victory placed rural Palestine at the mercy of the
invaders and they were encouraged to further enterprises.
The tribes of Arabia were united in a measure by their recent
conversion to Islam and were therefore in a position to form
a common plan and to co-operate in the execution of it.
Early in 635 they advanced towards Damascus, driving Greek
forces before them. Engagements were fought at Beisan
(January 635) and at Merj es-Suffar (February 635) on the
way. The surrender of Damascus in the beginning of
September was an act of the inhabitants who began to see
that the Arabs were an alternative to the hated Byzantine
governors.
Heraclius now made his one great effort to save Syria.
In the summer of 636 an army of imperial mercenaries and
Armenians and Arabs (drawn from the settled tribes of Syria)
advanced through the Biqa‘ and past Baniyas and across the
Jordan, south of Lake Huleh. They cut the communication
between Damascus and Arabia. But the Arabs had already
abandoned Damascus and had taken their position on a strong
line of defence, just south of the River Yarmuk. The opposing
armies seem to have faced one another on opposite sides of
the Yarmuk for some weeks. Futile negotiations were
carried on. Perhaps both sides awaited reinforcements and
feared to risk attack. Apparently the Greeks at length took
the offensive. The Arab victory was of supreme importance
for the future of Islam and therefore for the history of the
world. Unfortunately the course of the battle cannot be
ascertained in detail. Certainly the Moslems were not greatly
superior in point of numbers. During one phase of the
struggle the Greeks appear to have been within sight of
victory. But the composite character of their army was
a disadvantage. Their leaders were at variance and perhaps
their full force was not employed. Although most of the
Arabs fought on foot they had a distinguished cavalry leader
(Khalid ibn Walid), who seems to have dealt the decisive
blow. A sand-storm blowing in the faces of the Greeks may
have turned the scale against them (August 20, 636).