Who won the Battle of Yarmouk?
In August 636, in fighting traditionally counted as six days, near the Yarmouk River on the edge of Syria, the Arab army of the Rashidun Caliphate under Khalid ibn al-Walid destroyed the main Byzantine field army. Khalid's fast, well-led horsemen wore the larger Byzantine force down and, with a dust-laden wind that the Byzantine chronicler Theophanes says blew into the Byzantines' faces, broke it completely. The victory ended centuries of Roman rule in Syria and opened the Levant to the early Muslim conquests.2
It is a decisive battle that most people have never heard of. On a dusty plateau above a river gorge, the eastern Roman Empire lost Syria, the Persian and Roman worlds began to give way to a new one, and the map of the Middle East was redrawn for centuries to come.3
A new power out of Arabia
In the 630s the armies of the new Rashidun Caliphate burst out of Arabia into the lands of the two great empires of the age, Byzantine Rome and Sasanian Persia, both exhausted by a long war against each other. Only a few years earlier the emperor Heraclius had beaten Persia, and in 630 he had personally returned the True Cross, carried off by the Persians in 614, to Jerusalem. The victory had cost the empire dearly, and the Arab attack fell on provinces that had barely been recovered.4 › Battle of Nineveh, 627
The Arab commanders moved fast. Khalid ibn al-Walid, sent first against Persian Iraq, crossed the desert into Syria with his men and their camels carrying water, and the Arabs beat a major Byzantine force at Ajnadayn in 634. Damascus surrendered in 635 by al-Baladhuri's account, which dates its conquest to Rajab of year 14 of the Hijra; Byzantine Palestine lost again at Fahl (Pella), and Emesa, today's Homs, fell early in 636. The new caliph Umar formally replaced Khalid as supreme commander in Syria with Abu Ubayda ibn al-Jarrah, but Khalid remained, Britannica says, the effective leader of the Arab forces facing the Byzantines.5
Heraclius gathers his army
Heraclius, directing the campaign from Antioch in northern Syria, gathered the largest army he could find to drive the Arabs out for good. It drew on Greeks, Armenians, Slavs and other contingents, and on the Christian Arab Ghassanids under their king Jabala ibn al-Ayham, who led the vanguard. Its field commander was the Armenian general Vahan, with the imperial treasurer Theodore beside him. The emperor himself, unlike in his Persian wars, did not take the field.6
Faced with this host, the Arab armies, scattered in at least four separate groups, pulled back. They abandoned Damascus and gathered south of the Yarmuk, where reinforcements from Medina reached them. Britannica credits Khalid with persuading a council of war to unite the whole army in one place. Talks between the two sides dragged on, by one account for about three months, while Heraclius waited in vain for help from his new Persian allies.7
Two armies on the plateau
The two armies faced each other for days on the plateau above the Yarmouk, a river running through deep gorges that would trap a beaten army. The Byzantine force was larger and mixed, with Greek, Armenian and Arab Christian contingents; the Arab army was smaller but united and highly mobile. Its nominal commander was Abu Ubayda, but the fighting was directed by Khalid ibn al-Walid, the ablest Arab general, who massed his best horsemen into a mobile reserve he could throw wherever the line bent.8
Behind the Arab line stood the camp, and women were there too. al-Baladhuri records that Muslim women fought in the battle, among them Hind, the mother of the future caliph Muawiya, who urged the men on against the enemy.9
Six days by the river
The fighting followed a pattern. On the first days the Byzantines attacked in strength, and more than once broke into the Arab line; the Arab flanks were driven back to their camp, where, the tradition says, the women shamed the fugitives into turning around. Each time Khalid led his cavalry reserve into the breach and restored the line. After four days of this, the Byzantines had spent their strength. Vahan is said to have opened talks again on the fifth day, and Khalid refused.10
Time had worked against the empire. Heraclius had meant to be cautious, wearing the Arabs down with small engagements while his diplomats talked and his Persian allies came up, but the Persians never arrived. His army, Britannica notes, was made up largely of Christian Arab, Armenian and other auxiliaries, and as the weeks passed many of them deserted. The Arabs, reinforced from Medina and united under one effective commander, grew stronger while the Byzantine host grew weaker.11
The storm and the rout
After days of attack and counterattack, the decisive blow came on the last day. According to Theophanes, a south wind drove dust into the faces of the Byzantines, and Khalid launched his massed horsemen against their flank and rear, cutting them off from their line of retreat. Pinned against the gorges, the great Byzantine army broke and was destroyed, many thousands killed in the rout and the ravines behind them.12
al-Baladhuri even claims that the Byzantines chained themselves together so that no one could set his hope on flight. Many of the fleeing troops fell to their deaths in the ravine or drowned in the river. Jabala and many of the Christian Arabs had already changed sides or slipped away during the battle, and Vahan was killed or, by another story, retired to a monastery.13
Farewell to Syria
Yarmouk shattered Byzantine power in the Levant. Damascus and the other cities fell for good, Jerusalem surrendered within a few years, and the empire pulled back behind the mountains of Anatolia. al-Baladhuri tells how Heraclius, hearing of the destruction of his army, left Antioch for Constantinople and, as he crossed the mountain pass into Anatolia, turned back and said: "Peace unto thee, O Syria, and what an excellent country this is for the enemy!"14
Britannica's account puts the surrender of Jerusalem in the following year, and has Heraclius concentrating from then on on the defense of Anatolia and Egypt. Egypt too fell within a few years. At about the same time, in 636 or 637, Arab armies won a similar victory over the Sasanian Persians at al-Qadisiyya. The battle was one of the most consequential in history, opening the whole Near East to the astonishing early spread of Islam.15 › Battle of Tours, 732
Khalid did not long enjoy his triumph. Umar removed him from command soon afterward, and he died in 642; tradition places his tomb at Homs, where a mosque bearing his name stands today. Britannica calls Yarmouk Khalid's greatest victory and a major factor in raising the power of the young caliphate over that of the Byzantine Empire across much of the region.16 › The Fall of Constantinople, 1453
How many fought, and when?
The numbers are the most uncertain part of the story. al-Baladhuri has Heraclius gather about 200,000 men against 24,000 Muslims and speaks of some 70,000 Byzantines killed. Modern estimates are far lower: Walter Kaegi puts the Byzantine army at 15,000 to 20,000, John Haldon at about 20,000, a figure he calls a guess, and Fred Donner, at the high end, at about 100,000. Britannica lists losses of about 40,000 on the Byzantine side and 5,000 on the Arab side.17
The date is uncertain too. al-Baladhuri places the battle in the month of Rajab of the year 15 of the Islamic calendar, which fell in August 636. Britannica's battle summary says the fighting began on 20 August and lasted six days, while its life of Khalid dates the destruction of the Byzantine army to 20 August. Dates of this period are given in the Julian calendar.18
