It is considered by some historians to have been one of the most significant battles in the history of the world, since it marked the first great wave of Muslim conquests outside Arabia, and heralded the rapid advance of Islam into Palestine, Syria and Mesopotamia.

The Roman emperor organized a force of about 70 000 troops for this battle. The advance of this large Roman army, caused the Muslims to abandon the cities, and retreat southward towards the River Yarmouk, a tributary of the River Jordan. First; Roman soldiers attacked Islam forces whose numbers were lesser than Romans. Despite this, Moslems' forces at first pushed back, but although this army was only about half the size of the Roman force, it was more unified. At least Moslem soldiers made an agreement together in order to fight for martyrdom.

Then; they attacked to enemy forces bravely. These bravely attacks caused renewed Muslim counter-attacks broke through the Roman lines, and a rout ensued. Most of Romans were either encircled and massacred.

During this battle, Roman forces were defeated and some of them escaped and about 3000 Moslem soldiers were martyred. During this battle, the Caliph died and the commandeer was changed, but the new commandeer did not released this news in that critical situation. In the beginning of war, one of the Roman commandeer accepted Islam religion and martyred in this battle.