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20 August 636 CEReputable source · 2 sourcesWell documented

The Battle of Yarmouk Opens Syria and the Levant to the Rashidun Caliphate

Khalid ibn al-Walid routs a Byzantine army after a six-day battle near the Yarmouk River

On the timeline · around 20 August 636 CE · The Rashidun Caliphs and the First FitnaPre-Islamic Arabia and the Life of MuhammadThe Rashidun Caliphs and the First FitnaThe Battle of Yarmouk Opens Syria and the Levant to the Rashidun Caliphate620 CE625 CE630 CE635 CE640 CE645 CE650 CE

Quick facts

Location
Yarmouk River, border of modern Syria/Jordan
Rashidun commander
Khalid ibn al-Walid
Byzantine emperor
Heraclius (r. 610-641 CE)
Aftermath
Jerusalem capitulates in 637 CE

What happened

After Abu Bakr sent four divisions to raid Syria, the Rashidun forces took Damascus in 634 CE and pushed north, drawing a major Byzantine counterattack under commanders sent by Emperor Heraclius. The general Khalid ibn al-Walid withdrew his forces south beyond the Yarmouk River to make a stand there, and the two armies fought for six days starting in August 636 CE. On the climactic morning of 20 August, Khalid ordered an advance and enveloped the Byzantine line with cavalry, and the imperial troops routed with heavy losses; their field commander likely died in the fighting. Jerusalem capitulated the following year after receiving safety guarantees personally from Caliph Umar, and the Jewish population that Rome had banished from the city five centuries earlier was allowed to return.

Why it matters

Yarmouk broke Byzantine military power in the region for good and opened Syria, Jordan, and Palestine to Rashidun control, redirecting the empire's remaining troops toward the Sassanian Persian front. It is one of the most decisive battles of the early conquests, converting a series of raids into the permanent loss of the Levant for Byzantium.

How we know

The battle's date, the six-day engagement, and Khalid's tactics are described in the World History Encyclopedia's account of the early Muslim conquests, drawing on the Arabic historical tradition for the campaign narrative.

Sources

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