The fall of Hira to the Muslim…
November 634 CE
The fall of Hira to the Muslim Arabs had shocked the Persians.
Rostam Farrokhzād, in the name of Yazdrgerd III, sends forces to the Arab border areas, and looks to be gaining the upper hand, as Al-Muthanna has to call for reinforcements from Medina.
The new Caliph, Umar, sends Abu Ubaid to Mesopotamia to take command from Al-Muthanna.
During Abu Ubaid's campaign in the Sawad in 634, Rostam Farrokhzād sends Bahman Jaduya against him with a force that includes elephants and the elite ten thousand-man unit within the Sassanian army known as Zhayedan (Immortals), bearing the army’s finest and preeminent quality weaponry and armor.
He turns the Muslims back at Babylon west of the Tigris, drives them across the Euphrates, and camps at Qoss al-Natef on the east bank.
Abu Ubaid camps across the river, and when he crosses the Euphrates on a floating bridge and attacks the Persians, Bahman Jaduya catches the Muslims with their backs to the river and inflicts a serious defeat on them in the Battle of the Bridge.
The sight of the elephants in the Sassanid army frightens the Arabs horses, and Abu Ubaid is trampled to death by an elephant.
The bridge is broken by an Arab, and around four thousand Arabs die by drowning, with many others killed by the Sassanid forces.
Al-Muthanna managed to flee from the bridge and rally three thousand Arab survivors, some of whom flee back to Medina.
Bahman does not pursue them.