Muthanna. Muthanna was a chief of the tribe of Bani Bakr who inhabited the northeastern part of Arabia. In the apostasy campaign in Bahrain, Muthanna and his band fought on the side of the Muslims. Records are silent as to when Muthanna became a Muslim. Presumably he became a Muslim during the lifetime of the Holy Prophet. When the wave of apostasy engulfed the Arabian Peninsula, Muthanna remained firm in his faith in Islam.
Conflict with Persia. In the apostasy campaign in Bahrain, the Persians had aided the apostates. After the successful termination of the apostasy campaigns, the stage was set for taking action against the Persians across the barriers, from whom trouble could be expected any time for the Muslim State. There was considerable disarray in the affairs of Persia, and the Arab tribes in Persian territory were dissatisfied with the Persian rule. Muthanna felt that this position could be exploited to the advantage of the Muslims, and the Arab tribes could be liberated from the Persian yoke.
Reconnaissance campaigns of Muthanna. With a band of his followers, Muthanna began his raids in Iraq. In the first instance he stuck to the periphery of the desert, so that in the case of danger, he could withdraw to the safety of the desert. Most of his raids were conducted in the region of Uballa in the lower valleys of the Tigris and the Euphrates. From these raids, Muthanna was able to collect much booty. The Persians were unable to take any action against Muthanna because his ghost-like riders struck rapidly and then disappeared into the desert.
Muthanna's visit to Abu Bakr. These reconnaissance campaigns which took the form of desultory raids brought home to Muthanna that Iraq was vulnerable, and that if active operations were undertaken there were prospects for success. Early in February 633 C.E., Muthanna went to Madina and saw Abu Bakr. He pointed out to the Caliph that the people who inhabited the border areas in Iraq were Arabs who legitimately belonged to Arabia, and that if the Muslims undertook campaigns to liberate such tribes from the irksome yoke of the Persians, that would be a step forward in history towards building a greater Arabia.
Decision of Abu Bakr. Abu Bakr listened patiently to all that Muthanna had to say. Abu Bakr was aware of the prophesies of the Holy Prophet that erelong Islam would spread to Iraq and Syria. Now that the apostasy campaigns had ended in victory for Islam, and the entire Arabia stood unified, Abu Bakr felt that if campaigns were undertaken beyond the borders of Arabia that would provide an outlet for the energies of the Muslims. Such campaigns, if successful, were also likely to bring considerable money. It would extend the sphere of the influence of Islam, and it would also lead to more people coming within the fold of Islam. Abu Bakr felt convinced that if Islam was to fulfil its destiny, it must necessarily expand. Abu Bakr held a council of war, and after due deliberation it was decided that in the name of God a campaign should be launched against Iraq. Muthanna was given the necessary aid and he was required to operate with his column on the Iraq front. He was assured that the main Muslim army under Khalid bin Walid would soon launch the attack against Iraq.