In order to add scholarly grandeur and status to his court and on the other hand...

In order to add scholarly grandeur and status to his court and on the other hand, reduce voices of dissent from the advocates of ‘Ali (as)'s household and compensate the atrocities he had committed in the past, Ma’mun decided to invite Imam al-Ridha (as) to Merv upon consultation with his close companions, especially Fadhl b. Sahl, a smart man who managed the state and military affairs. Ma’mun asked Imam al-Ridha (as) importunately to go to Merv from Medina.

He had in mind, by this invitation, to reinforce the pillars of his rule and perhaps to discourage the Imam (as)'s position by drawing him to the core of the ruling system. Ma’mun, himself a learned and clever man, was more than anybody else aware of Imam al-Ridha (as)'s vast field of knowledge and piety and virtue. Fadhl b.

Sahl, too, knew about the spiritual power of the the Imam (as) and was well-aware that the intuition, purity, and sincerity of the descendant of the Holy Prophet (S) had so widely spread around that people were spiritually prepared to welcome his leadership wholeheartedly. Having decided to invite the Holy Imam (as), Ma’mun dispatched Raja’ b. Abi Dhahhak along with some trusted courtiers to Medina to persuade Imam al-Ridha (as) to travel to Khurasan.

At first, Imam al-Ridha (as) did not give his consent to their invitation, letting people infer what secret and covert plans the ruling system was harboring by inviting him. Finally, upon much insistence from Ma’mun, Imam al-Ridha (as) agreed to leave for Khurasan through Mecca and Iraq.

Imam al-Ridha (as) said a heartrending and distressful farewell to the illuminated tomb of his noble ancestor, the Holy Prophet (S), all members of his family, and even his cherished only-child and successor Imam Muhammad al-Taqi al-Jawad (as). The luxurious camel-litters and the retinue provided by the ruling system together with the entourage consisting of the governor and the nobles of Medina accompanied the Holy Imam (as) with utmost grandeur and splendor to Basra.

How was it possible for Ma’mun, who had decided on killing his brother Amin and bringing his head to the capital to hold a festival for rewarding a bounty to the one who would manage to murder the latter, to renounce caliphate and turn it over to ‘Ali (as)'s household?! It was unbelievable.