Battle of the River Yarmuk
Inspired by their new religious faith (the Prophet Mohammed had only died in 632) Arab armies advance upon both the Persian Empire, which is soon absorbed, and the Byzantine Empire.
At first slow to react, the Byzantines finally mobilise a large army against the Arabs. Badly handled and out-fought, the Byzantine Army is destroyed by the Arabs at the Battle of Yarmuk, in Syria.
Already ravaged by the Persian war, Byzantine provinces in the Middle East and North Africa fall quickly to the Arabs. The Byzantines fall back, holding the mountain passes of eastern Asia Minor against further Arab encroachment.
The Arabs establish a powerful state, the Omayyad Caliphate, based around the capital city of Damascus.