In the history of al-Tabari, it was stated that Khosrow the second (590-628 AD), known as Khosrow Parviz, followed the steps of his ancestors, the kings who went to war with the Byzantines. He reached Chalcedon, and took over the Levant, and his armies entered Jerusalem in 614 AD, then they took over Egypt in 619 AD.With his conquests, he exhausted the Romans until his son overthrew him. Thus, they managed to recover from the Persians more than they robbed them off in those wars. These successive wars weakened the Sassanidic government, and the formation of their army became based on soldiers who had been forcibly brought to the army in a way “forced labor,” and it amounts to torture.

When the battle of Dhi Qar took place, the Arabs were then able to change the borders, and the influence of the Sassanid soldiers. The battle had strengthened them, and taught them the weaknesses of the Sassanids. When Islam spread from the Arabian Peninsula, it became a help in undermining the Persian Empire, and uncovering the weaknesses in it. As Islam spread overseas, it undermined the huge government with surprising speed. The warriors had learnt about the methods of organized fighting in such huge battles, that they were to encounter, for the first time, in their wars with the Sassanids and Byzantines.  And so was the story written in the history of the Arabs before Islam.

The Arab tribes realized the weakness of Al-Hirah as they were not  able to protect  trade routes and secure goods in the markets of the Hijaz and Yemen. Such weakness was caused by internal strife and ongoing conflicts over governance. Thus, the tribes attempted to attack the kings of Al-Hirah and the borders of the Persians at the same time. Perhaps, these raids were among the reasons that led to ending the rule of Al-Nu’man, so he decided to replace him with another Arab or a strong man from the leaders of the armies loyal to the Persians.

Either because he thought so or because of the news that Al-Nu’man was negotiating with the leaders of the tribes to satisfy them and include them. With what he did, he threatened the interests of the Persians and tried to separate himself from them. Thus, the Persians wanted to eliminate him along with the ruling family, before he was able to obtain the support of those leaders, who realized the weaknesses in the Sassanian government.

There are narratives such as Ibn Abed Rabbo in his unique contract: “Al-Nu’man told the tribal leaders that He was only a man of your own, and the rest of the Arabs shall be aware of this and believe it.” Such narrative and many more had driven Khosrow to kill Al-Nu’man.  Such narratives had driven Khosrow to believe that Al-Nu’man and his family attempted to gain the support of the tribal leaders against the Sassanids. Moreover, the inability of the kings to protect the convoys of Persians going to and returning from Yemen- the important trade routes that connect Iraq with Yemen-, the inability of the kings to prevent the Arabs from raiding the borders of the Sassanids, and the attempt of King Al-Nu’man to contact the tribal leaders to gain their support against the Persians, are, definitely, the reasons why Khosrow assassinated the king of Al-Hirah, and replaced his ruling family with another loyal one.

The Persians assigned a ruler of them over Al-Hirah but he was unable to prevent the Arabs from crossing the borders. They were exhausted, while the Arabs came with a message, and with such determination to make a change, even before “Dhi Qar,” hence, its aftermath was, truly, heavy for the Persians.