The main focus of the writers of the beforehand study, without ignoring other reasons of Persians' downfall in the Mongol Invasion, has been studying psychological elements of this defeat. We believe that Sultan Muhammad and consequently Iranians were afflicted with a kind of acquired insolvency and breakdown. Thus, primarily, the progression of Sultan Muhammad's ever-increasing power is collected, in detail, which would be used as a psychological background for people's surrender and acceptance of defeat. In the process of Sultan's overall submission to Genghis and the Mongols, it is acceptable that some factors such as Turkan Khatoon's influence on her son, superstitions, accusing extremists, who were against the invasion of Baghdad and the caliphate, of rebellion, reduction of validity and legitimacy of religion, people's discontent of him and his agents in different regions, drawbacks of ostracism, and punishment of influential clerics, clarify the defeat. But, any of these elements, and all of them as a collection, was the existing factors of all Iranian monarchies; what happened to the King, Iran, and the Iranians during the Mongol Invasion is of another kind. Historical documentation presents evidences of the king's ineffectual behavior.His escape and circumvention from the Mongols was strengthening their courage and transferring his potential fear to Iranians. The end result of this severe fear was an acquired feebleness which refuted any effort in obtaining the desired result. The mingling of this incapacity with fatalism, which the king and the nobility commonly promoted it, brought about the most ominous defeat, which in Bin Asir's viewpoint, no other nation will experience the same failure till the end of history.