[^3] It is also narrated that a lengthy discussion went on...

[^3] It is also narrated that a lengthy discussion went on between both men in which al-Ma’mun offered the Imam to be the caliph and the Imam refused to accept, then he offered him the regency and he refused too, so al-Ma’mun said to him, "You always say what I hate to hear, and you think that you are safe from my might; therefore, I swear by God that you should either accept the regency willingly or I shall force you to do so; therefore, accept out of your own will; otherwise, I shall certainly strike your neck with the sword." [^4] Al-Ma’mun Reveals His Intentions Al-Ma’mun himself revealed to us the far-sighted implication of his choice for regent in a letter to Banu Hashim answering their objections regarding the promise of regency to the Imam in which he said: "As regarding my intention behind choosing Ali ibn Musa (a.s.) as the regent, although he is qualified for it, out of my own selection of him, the reason for that is my desire to safeguard your lives and protect your properties by establishing permanent friendly ties between us and them, and it is a method I employed to honor the descendants of Abu Talib and to heel their wounds with very little of what they are entitled to.

You claim that I desired that they would be the recipients of benefits thereof and to be in charge, while I have in mind the interest of your posterity and children after you even while you are unaware, blindly stumbling, not knowing what plans others have in store for you." [^5] He does not wish to transfer the government from Banu al-Abbas to the descendants of Abu Talib, as the Abbasides imagined; rather, he aimed by such an action to contain the consequences which might cause a great deal of trouble for the government.

In other words, he aimed by taking such a political action, to retain a position of strength for the Abbasides.

Al-Ma’mun and the Astronomer Nawbakhti What proves the fact that al-Ma’mun was not serious in his offer to the Imam to be the regent is a narration stating that al-Fadl al-Nawbakhti, who was an astronomer thought to be Shi'a, wanted to test al-Ma’mun's intentions, so he wrote him saying: "The order of the stars indicates that naming ar-Ridha’ (a.s.) as the regent at this time cannot be done; otherwise, the person named will suffer a catastrophe.