Persian forces. After the victory of Daumatul Jandal, Khalid returned to the Iraq front in September 633 C.E. By this time, the Persians had raised more forces and they were once again on the war path. One force of the Persians commanded by Ruzbeh was quartered at Huseid, northeast of 'Ein-at-Tarur. Another Persian force under Zarmahr was cantoned at Khanafis northwest of Huseid.
Plan of the campaign of Khalid. Khalid had his headquarters at 'Ein-at-Tarur. From there he sent one column under Qa'qa' to Huseid, and another column under Abu Leila to Khanafis. The instructions of Khalid were that the operations at Huseid and Khanafis should take place simultaneously.
The battle of Huseid. Qa'qa' reached Huseid before Abu Leila could reach Khanafis, and thus the original plan of simultaneous action could not be followed. The battle at Huseid began with a personal duel between Qa'qa' and Ruzbeh. In the duel, Ruzbeh was overpowered and killed. Then Zarmahr, the Commander of the forces at Khanafis, who was also at Huseid, stepped to give the challenge. Qa'qa' accepted the challenge and in the duel that followed, Zarmahr was also killed. Thereafter the Muslims charged. After some resistance, the Persians lost nerve, and withdrew from the battlefield leaving a large number of the dead at the site of the battle.
Confrontation at Khanafis. The survivors of the Persian army from Huseid fled to Khanafis. When the Persian garrison at Khanafis came to know of the Persian defeat at Huseid and of the death of their own Commander Zarmahr, they felt that any stand at Khanafis against the superior Muslim forces would be futile. Mabhuzab the new Commander considered discretion to be the better part of valor. He abandoned Khanafis and with his forces moved to Muzayyah further north where more forces were available and defenses were stronger. When the Muslim forces under Abu Leila arrived at Khanafis, they found that there were no Persian forces to meet them. The Muslims accordingly occupied Khanafis without firing any shot. Khalid, however, was not happy with the operations for the entire Persian garrison at Khanafis had escaped slaughter at the hands of the Muslims.
March to Muzayyah. When Khalid came to know that the Persian garrison from Khanafis had escaped to Muzayyah, he directed that the Persians should be pursued to Muzayyah. Three Muslim columns started separately for Muzayyah from 'Ein-at-Tamr, Huseid and Khanafis. They had to follow different routes, but they were required to reach a point close to Muzayyah at the same time.
The battle of Muzayyah. The movements of the Muslim forces were carried out according to plan, and the three corps mustered at the appointed place according to schedule. In the Persian camp there was a large concentration of the Persian forces and the Christian Arab auxiliaries at Muzayyah. Muzayyah was at considerable distance from Huseid and Khanafis, and the Persians were under the impression that the Muslim forces would take considerable time to reach Muzayyah.
When the Muslim forces reached unexpectedly at Muzayyah, it was night and the Persians and the Christian Arabs slept peacefully. Roaring masses of Muslim warriors hurled themselves on the Persian camp. So sudden was the Muslim attack that Persian army was unable to take any firm stand. There was confusion and panic in the ranks of the Persian army, and the Persians were slaughtered in thousands. The disaster that met the Persians at Muzayyah was more or less of the same order as they had suffered at Walaja. Helped by the darkness of the night many Persians and their auxiliaries found safety in withdrawing from the battlefield.
When the sun rose the following day, not a single Persian soldier could be seen at Muzayyah. Most of them lay dead at the battlefield, and the rest had found safety in flight. Among the Arabs who had lost their lives at Muzayyah were two persons, Abdullah and Labid who were Muslims and had certificates to that effect from Abu Bakr himself. Some of the critics of Khalid held him guilty of killing Muslims. Abu Bakr held that such things were likely to occur when Muslims chose to live in the midst of non-Muslims, against whom military operations were undertaken. Abu Bakr, however, paid blood money to the heirs of the two persons from the Muslim Baitul Mall.
Battle of Saniyy. The victory of the Muslims at Muzayyah exposed the Christian Arab pockets of Saniyy, Zumeil, and Ruzab to Muslim attack. Saniyy being close to Muzayyah become the first objective of the attack of the Muslim forces. From Muzayyah three Muslim columns marched through separate routes and arrived at Saniyy according to plan on pre-determined time and date. A three pronged attack was launched on the Christian Arab camp at Saniyy. The Christian Arabs were no match for the trained forces of Khalid and were slaughtered in thousands. The Christian Arab Commander Rabee a bin Bujeir was slain on the battlefield. Among the captives was the beautiful daughter of Rabee'a. She was sent to Madina, where Ali married her.
Battle of Zumeil. From Saniyy the Muslim forces marched to Zumeil. Here again a three pronged attack was launched by three columns according to a pre-determined plan. The Christian Arab forces at Zumeil met with disaster and were annihilated. The Muslims won considerable booty both at Saniyy and Zumeil.
Battle of Ruzeb. From Zumeil, the Muslim forces proceeded to Ruzab. Here Hilal the son of the Christian Arab chief Aqqa who had fallen at 'Ein-at-Tamr had collected a large force of the Christian Arabs to give a fight to the Muslims and avenge his father's death. When Hilal came to know of the fate of the Christian Arabs at Saniyy and Zumeil, he lost heart. When the Muslim forces arrived at Ruzab, there was no enemy to oppose them, and they occupied Ruzab without any resistance. Hilal and his forces withdrew before the arrival of the Muslims.
Muslim domination. With the completion of these operations, the entire region to the west of the Euphrates from Uballa to Anbar came under the complete domination of the Muslims; all pockets of the Persians of the Christian Arabs in this region were completely liquidated.