The Muslims under the command of Abu Ubaid had won a few initial successes against the Persians. That emboldened Abu Ubaid.
The Persians now sent another force under Bahman. Bahman was a veteran General of considerable standing, and he undertook to drive away the Arabs from the soils of Persia.
Bahman marched with his army towards Hira and camped at Quss Natif on the east bank of the Euphrates some distance north of Hira, and little below the site of Kufa.
When Abu Ubaid came to know of the movements of the Persian army, he marched the Muslim forces from Hira and camped with 9,000 men on the west bank of the Euphrates at the village called Marauha.
Now the river Euphrates lay between the two forces, Bahman sent an emissary to Abu Ubaid with the message "Either you cross and come over to our side; or we will cross and come over to your side."
Abu Ubaid was advised that he should ask the Persiaus to cross. The Persian emissary played on the emotions of Abu Ubaid, and said that in the Persian camp the general belief was that the Muslims were afraid of the might of Persia. Abu Ubaid made him understand that one Arab was equal to ten Persians. The emissary said that if such claim was not an empty boast, the Muslims should substantiate it by taking the initiative and crossing over to the Persian side. In a vainglorious mood Abu Ubaid declared, "We will cross the river; go and tell your Commander accordingly."
As soon as the Persian emissary had left, Abu Ubaid ordered that the Muslim forces should prepare for crossing the river. Saleet bin Qais who had been appointed by Umar as the Adviser to Abu Ubaid told Abu Ubaid that his decision to cross the river was not sound. Abu Ubaid retorted "Saleet, you are frightened Have trust in God."
Muthanna who commanded the cavalry also tried to persuade Abu Ubaid reconsider his decision. Abu Ubaid remained adamant and he removed Muthanna from the commend of the cavalry. In his place he appointed his cousin Abu Mihjan to the command of the cavalry.
Some other veterans in the Muslim army said to Abu Ubaid, "O Commander do not cut your means of escape, and do not make yourself a target of the Persians." Abu Ubaid said that such were the counsels of the chicken-hearted, and I that those who were fighting in the way of God should have the courage and boldness to beard the lion in its den.
The previous night, Dauma the wife of Abu Ubaid who was with him in the camp had a dream. In the dream she had seen a man come down from heaven with a vessel from I which Abu Ubaid drank. Thereafter his brother al-Hakam drank from it. Next his son had a drink from it, and then some other members of the tribe of Abu Ubaid drank from the vessel. After all had drunk the person concerned carried the vessel back to the heaven.
When Dauma related her dream to Abu Ubaid, he interpreted it to mean that he and all the other people who had drunk from the vessel would be blessed with martyrdom. That did not in any way unnerve Abu Ubaid. On the other hand he felt happy at the prospects of martyrdom.
A bridge of boats was thrown across the river, and the Muslim army marched along the bridge on the morning of 28th November 634 A D. The Persians watched the Muslim army cross the river. They, however remained arrayed in battle order in light formation.
As the Muslim army crossed over to the other side of the river they found that the space at their disposal was circumscribed, and there was no room for any manoeuvres or out" flanking movements.
Immediately after crossing, the Muslims formed themselves into battle formation and faced the Persian hosts. The Persian army had with them a large number of war elephants. Each elephant carried a howdah in which sat soldiers armed with javelins and bows. To each howdah branches of palm trees were tied to give the illusion of size. Bells were tied round the neck of the elephants, and these appeared to produce an unearthly din.
When the battle began the Muslim cavalry advanced to the charge. At the sight of the monster elephants the Arab horse shied, turned, and bolted. That led to confusion and the Muslim cavalry was disorganised.
Seeing this confusion in the Muslim ranks, Bahman ordered an advance by the Persian forces. As the Persian forces advanced the noise from the bells of the elephants became louder. Th Persians seated in the howdahs of the elephants made good use of their bows and arrows and drove several wedges in the Muslim front.
At this stage Abu Ubaid ordered the Muslim cavalry to dismount and attack on foot Abu Ubaid himself led the attack. He exhorted his men to attack the elephants and cut their girths. In the attempt many Muslims were killed, but some Muslims succeeded in cutting the girths of some elephants. Abu Ubaid rushed at the leading elephant, a white monster elephant, with his javelin. The beast was blinded in one eye. Then Abu Ubaid got under the elephant and cut its girth bringing down the howdah and its occupants. In the scuffle that followed the elephant knocked down Abu Ubaid and trampled him under its heavy foot.
Al Hakam the brother of Abu Ubaida rushed to the spot. He shot the animal dead. He picked up the standard and led fighting. After some time he too fell fighting and the command was taken over by Jabr the son of Abu Ubaid. The battle waged with unrelenting fury and one after another all the Muslim commanders were martyred. All those whom Dauma the wife of Abu Ubaid had seen drink from the vessel brought from the heaven tasted martyrdom.
The Persians increased the violence of their attack and the Muslims fell back. At this stage Abdullah bin Marthad who belonged to the clan of Abu Ubaid cut off the boat bridge and to those who sought the bridge he shouted' O people die for what your Commanders have died." Some people turned back to fight and fell dead at the battle-field. Others plunged in the river and were drowned.
The Muslim forces were at this stage without a Commander, and the Persians increased the violence of their assaults. At this critical moment Muihanna took command of the army. He ordered the bridge to be rebuilt and when it was ready he organised a rear guard action. With a select force he faced the Persians, and asked the others to cross calmly without being panicky. Muthanna and his reserves remained at their posts until the entire army had crossed. Muthanna was the last to cross. In guarding the bridge he had received innumerable wounds and as he reach the Muslim camp he fell exhausted.
As the Muslim forces assembled at Marauha on the other side of the Euphrates, only 3,0OO persons assembled out of the total strength of 9,000. Some 2,000 persons fell fighting, some 2000 persons were drowned in the river, and some 2,000 persons fled away to Madina and elsewhere.
The immediate worry of Muthanna was pursuit by the Persians. If in the wake of their victory the Persians had crossed the Euphrates, all that had been left of the Muslim army would not have been able to face the Persians. Bahman felt elated at his victory over the Muslims. He had demonstrated that the Persians were still a mighty force. He had a mind to pursue the Muslims across the Euphrates but at that crucial moment there was a revolt against Rustam at the Persian capital, and Rustam recalled Bahman to al-Madain to help in putting down the revolt.
When the scouts brought the news that the Persians were marching back to al-Madain Muthanna felt relieved. Hira was now unsafe for the Muslims. Muthanna accordingly abandoned Hira and marched with his weary army to Ulleis.
Abdullah bin Zaid carried the news of the tragedy of the Battle of the Bridge to Madina. Umar felt grieved at the reverse of the Muslims, but the disaster did not unnerve him in any way.
In this moment of crisis Umar rose to great heights of leadership. Instead of apportioning blame, he said:
"O Lord every Muslim is in my charge and I am a refuge for all Muslims. May Allah bless Abu Ubaid. Having crossed the river he should have secured his position by the side of a hill. I wish he had not crossed, and sought his death, but had returned to me."
Some persons who had fled from the battle-field and had returned to Madina wept bitterly at the disaster. To them, Umar consoled with the following words:
"Do not weep. I am your refuge, and you have returned to me."
To Muthanna at Ulleis, Umar sent the message:
"Stay at your post. Help will soon come."