Battle of Zumail The battle of Zumail was fought in 633 CE in what is now Iraq . It was a major Muslim victory in their conquest of that area . Under cover of night the Muslims attacked the Christian - Arab forces from three different sides . The Christian - Arab forces were unable to withstand the Muslim ' s surprise attack and soon dispersed but failed to escape from the battle field and became the victims of a three sided attack by Khalid ibn al - Walid ' s army . At Zumail nearly the whole Christian Arab army was slaughtered by Khalid ' s Corps . Background . When Khalid ibn Walid gone from Ain - ul - Tamr to Daumat ul jandal for the help of Ayadh . The Persian court believed that Khalid had returned to Arabia with a large part of his army , Persians decided to throw the Muslims back into the desert and regain the territories and the prestige which the Empire had lost . The Persians had resolved not to fight Khalid again , but they were quite prepared to fight the Muslims without Khalid ibn al - Walid . Khalid ibn al - Walid first defeated them at the battle of Muzayyah and then advanced towards Saniyy and defeated the Arab army there and finally defeated the last army at Zumail . By now Bahman had organised a new army , made up partly of the survivors of the Battle of Ullais , partly of veterans drawn from garrisons in other parts of the Empire , and partly of fresh recruits . This army was now ready for battle . With its numerous raw recruits , however , it was not of the same quality as the armies which had fought Muslims south of the Euphrates . Bahman decided not to commit this army to battle until its strength had been augmented by the large forces of Christian Arabs who remained loyal to the Empire . He therefore initiated parleys with the Arabs . The Christian Arabs responded willingly and eagerly to the overtures of the Persian court . Apart from the defeat at Ain - ul - Tamr , the incensed Arabs of this area also sought revenge for the killing of their great chief , Aqqa . They were anxious , too , to regain the lands which they had lost to the Muslims , and to free the comrades who had been captured by the invaders . A large number of clans began to prepare for war . Bahman divided the Persian forces into two field armies and sent them off from Ctesiphon . One , under Ruzbeh , moved to Husaid , and the other , under Zarmahr , moved to Khanafis . For the moment these two armies were located in separate areas for ease of movement and administration , but they were not to proceed beyond these locations until the Christian Arabs were ready for battle . Bahman planned to concentrate the entire imperial army to either await a Muslim attack or march south to fight the Muslims at Hira . But the Christian Arabs were not yet ready . They were forming into two groups : the first , under a chief named Huzail bin Imran , was concentrating at Muzayyah ; the second , under the chief Rabi ' a bin Bujair , was gathering at two places close to each other - Saniyy and Zumail These two groups , when ready , would join the Persians and form one large , powerful army . This was the situation that greeted Khalid on his arrival at Hira from Daumat - ul - Jnadal in the fourth week of September 633 . The situation could assume dangerous proportions , but only if the four imperial forces succeeded in uniting and took offensive action against Hira . Khalid decided to fight and destroy each imperial force separately . With this strategy in mind , he divided the Muslim garrison of Hira into two corps , one of which he placed under Qaqa and the other under Abu Laila . Khalid sent them both to Ain - ul - Tamr , where he would join them a little later , after the troops who had fought at Daumat - ul - Jandal had been rested . A few days later , the entire Muslim army was concentrated at Ain - ut - Tamr , except for a small garrison left under Ayadh bin Ghanam to look after Hira . The army was now organised in three corps of about 5 , 000 men each , one of which was kept in reserve . Khalid sent Qaqa to Husaid and Abu Laila to Khanafis with orders to destroy the Persian armies at those places . It was Khalid ' s intention to fight both Persian armies speedily as well as simultaneously , so that neither could get away while the other was being slashed to pieces . But this was not to be ; for the march to Khanafis was longer than to Husaid , and Abu Laila failed to move his forces with sufficient speed to make up for this difference . Meanwhile , Khalid remained with his reserve corps at Ain - ut - Tamr to guard against any offensive movement from Saniyy and Zumail towards Hira . Qaqa defeated the Persian army at Husaid , the remaining army retreated to Khanafis , where when the commander of the army at Khanafis heard about the Muslim ' s victory at Husaid withdraw his forces to Muzayyah and joined the Christian Arabs . At Muzayyah , that army was defeated in the Battle of Muzayyah later the same was done to the army at Saniyy . The manoeuvre of Khalid . The remaining objectives were Muzayyah , the Saniyy and Zumial . Khalid ibn al - Walid selected Muzayyah . The other was a smaller objective and could be dealt with later without difficulty as by now the exact location of the imperial camps at Muzayyah , Saniyy and Zumial had been established by Khalid ' s agents , and to deal with this objective he designed a manoeuvre which , seldom practised in history , is one of the most difficult to control and co - ordinate - a simultaneous converging attack from three directions made " at night . " The battle . After two or three nights of the battle of Saniyy , Khalid ' s Three Corps reached Zumail at night and attacked the Christian Arab forces from three different sides as planned before . The Christian Arab forces were unable to withstand the Muslim ' s surprise attack and soon dispersed but failed to escape from the battlefield and became the victims of a three sided attack by Khalid ibn al - Walid ' s army . At Zumail , nearly the whole Christian Arab army was slaughtered by Khalid ' s Corps . Aftermath . These battles ended the Persian control in Iraq , which finally fell to the Islamic Caliphate .