How the Jihad ravaged Christian Byzantium for 800 years, and how valiantly the Byzantine Christians held back the Arab and Turkish hordes, saving Europe from Islam. [ Full title ]. While the Zoroastrian Persians were defeated and were being subjugated, the Muslim hordes turned on their other neighbor the Christian Byzantines. The two armies met at the battlefield of Heiromyak. Lessons from the Battle of Heiromyak (Al Yarmuk). At the Battle of the Yarmuk (river), between the Muslim Arabs and the Byzantines, the Muslim Arabs were losing the battle in the initial stages. When the victory seemed certain for the...