After his noble father's martyrdom in the year 183 A.H., Imam Reza (PBUH), at the age of 35, undertook the Imamate. His Imamate's Period lasted for twenty years. The first ten years was contemporary with Harun al-Rashid's caliphate, five years with Muhammad Amin and the last five years was contemporary with Abdullah al-Ma'mun. By Imam Musa al-Kazem's (PBUH) martyrdom, Abbasids' anti-Alawite policy failed. People tended to Ahl al-Bayt more than ever and this tendency even penetrated among the families of caliphs and couriers. As it is said, Zubaidah, Rashid's wife, who was Mansour's grandchild and Abbasid's greatest woman, became a Shia, and once Harun al-Rashid found out about this, he swore to divorce her. It's been narrated that when Imam Kazem's (PBUH) body was brought among the state guards, and the news of his death was announced with indecent words, Soloman, Mansour's son, ordered his children and slaves to stop that. He, himself, followed the body barefooted and informed Harun al-Rashid by sending him a letter. Harun responded, "Dear uncle, thanks for greeting me, God rewards you with good; I swear to God, Sindi bin Shahak has not done this by my command”.
All of this was organized for the fear of Alawaite riots. As regards, Soloman ibn Abi Jafar was also one of the Abbasid state elites. This saying is confirmed by Harun's statements in response to Yahiya bin Khalid Barmaki. Yahiya first slandered Imam Kazem (PBUH) and then planned for his martyrdom. Then he told Harun about Imam Reza (PBUH) that “after Musa ibn-Jafar, his son claims that he should be Imam”. Harun was terrified of Musa ibn-Jafar's death consequences, and told Yahiya, “Isn't it enough what we did to his father? Do you want me to take the sword and kill all Alawites at once?”
Imam Reza (PBUH) took the chance and clearly announced his Imamate while we know that Imam Sadiq (PBUH) introduced five people as his successors so that the selected one would be safe form the enemies. Thus, we should say that Abbasids were afraid of the Alawites or were busy with the internal conflicts between the two brothers Amin and Ma'mun during the initial fifteen years of his Imamate. Finally, five days before the end of Muharram in the year 198 A.H., Amin was deposed from the caliphate and then murdered. At this time, independent states like Edareseh and Aghlabeh were formed and Abu al-Saraya uprising happened. More than twenty thousand people participated in this uprising and many cities were captured by the rebels. In the year 199 A.H., Abu al-Saraya was killed by Ma'mun’s army.
Imam Reza (PBUH) as the crown prince
Ma'mun's own instability of character, uprisings and the formation of independent states in a short time, made him resort to Abbasids' old policy of adopting slogans in favor of the Alawites, by which they had taken over the caliphate, and to save the Abbasid regime from an inevitable collapse with subtle prudence. Most of the independent governments and most of the uprisings and their leaders were from the prophet's family. In Abu al-Saraya uprising, two of Imam Reza's (PBUH) brothers took over Yemen and Ahvaz. Ma'mun who was aware of Ali ibn Mūsā al-Rida's (PBUH) Imamate after Imam Kadhem's martyrdom, announced him as the crown prince to calm the Shias revolutions and uprisings. Ahmad Shebli says “… Probably, Ma'mun's motive for taking Bay'ah from Imam Reza as the crown prince has been the fact that he wanted to respond to aspirations of the people of Khorasan, since they were more tended to Imam Ali's (PBUH) families.
Allama Jafar Morteza Hosseini says, “In evaluating the anti Abbasid uprisings, we'll realize this point that they were threatened by a series of dangers on the behalf of the Alawites. Because these riots rose on very sensitive areas and their leaders were wise and eligible and in this respect they have never been comparable to the Abbasids. The fact that people respected the leaders of these riots and responded to their invitations quickly was a proof to the people's level of understanding of the Abbasid caliphate and the intensity of their tyranny which was stimulated because of despotism cruel behavior towards people, specifically towards the Alawites. In the meantime, Ma'mun was well aware that if Imam Reza (PBUH) wanted to take the chance and deepen his influence against the current government, what was going to happen. With regard to the situation, Ma'mun had to do something to get rid of his doom. Suppressing the Alawites riots, legitimizing the Abbasids' government, eliminating Alawites' popularity, earning Arabs’ trust, pleasing the Abbasids, making Iranian's approval continuous, strengthening public trust towards the caliph who has killed his own brother and eliminating the danger of Razavi uprising were some parts of the facts that made Ma'mun think of this plot. He decided to take people's Bay'ah for Imam Reza's (PBUH) caliphate, so that he could introduce him as the Muslim's caliphate for both the Abbasids and the Talebians. Imam Reza (PBUH) rejected his offer. Ma'mun's insistence and Imam's rejection continued for two months. Eventually, the caliph sent Imam Reza (PBUH) this massage: “You always treat me in a bad way, although I have secured you from my outrage. I swear to God, if you don't accept the crown prince position, I'll force you to do it, and if you still decline it, I'll decapitate you.”
Needless to say, the caliphate offer had never been serious. How was it possible for a man who has killed his own brother for that position to give it to Imam? This plan was a start to Imam Reza's (PBUH) becoming the crown prince; Imam (PBUH) stated the reason for accepting that offer as follows:
1. One day Ibn Arfeh asked Imam (PBUH), “What was your motive for accepting this offer and becoming the crown prince?” Imam (PBUH) answered, “With the same motive that my ancestor Ali (PBUH) participated in the council”.
2. Imam (PBUH), in response to Ryan, one of his companions, stated, “…God knows how much I hate this but I was forced to choose between being killed and accepting the crown prince position… in fact I accepted that out of necessity and I was under pressure. In this narrative, Imam resembled accepting the crown prince passion by himself to accepting the position of treasury ministry by Prophet Joseph.
Ma'mun, in response to Abbasids complaints about Imam Reza becoming the crown prince, stated, "This man is hiding what he does and invites people to accept his Imamate. We appointed him as the crown prince so that he invites people to serve us and confess to our caliphate. Besides, his devotees should know that he is not as good as he claims, and I am the qualified one for this position (to be the caliph) not he. Also, we were afraid that if we left him alone, he would create a gap in our caliphate which we could not fill and that he would take actions against us that we could not resist. Now that he has adopted this procedure, we made a mistake and by giving more credit than we should have, we've put ourselves on the edge, and we shall not neglect him. Therefore, we should diminish his character and magnitude; we should make it look like he isn't qualified for this position. Then, we should do something about this and avoid its possible risks".
Imam Reza's Migration to Iran
When Amin was killed and Ma'mun's regime was established, Ma'mun asked Imam Reza in different letters to come to Khorasan along with Alawites elites and when Imam rejected his offer, a courier was sent to Medina to bring Imam (PBUH). Al-saduq quotes from Sijistani that “when the courier entered Medina to take Imam (PBUH) with him I was there. Imam came to the shrine to say goodbye to the Prophet (PBUH). I saw him coming out of the shrine and going back in there for several times and he was also crying. I got close to Imam (PBUH) and said hello and asked him why he was crying. Imam (PBUH) responded, “I'll leave my ancestor and I'll die alone'”.
Hassan ibn Ali Vasha quotes Imam telling him, “When they wanted to get me out of Medina, I gathered my family members and ordered them to cry for me so that I could hear their voice. Then, I divided 12000 dinars among them and said, ‘I will not come back to you ever again’”. Ma'mun ordered them to take Imam (PBUH) to Merv from Basra, Ahvaz and Fars. Because he was afraid if he took Imam (PBUH) from Kufa, Jabal and Qom, the compassion of the Shias in the mentioned cities might endanger Ma'mun's regime. The book "Qom History" which is one the oldest books available in the Shias’ community, states Imam Reza's (PBUH) migration as follows: "According to Raja Ibn Zahak, Ma’mun brought Imam (PBUH) from Medina to Merv and took Bay'ah from him in the year 200 A.H. and then poisoned him in Toos and on Monday six days left from Safar in 203 A.H. he was buried, he lived for about 49 years and a few months, he was the crown prince for 2 years and four months and his tomb is in one of the villages near Toos which is called Sanabad, near a place called Noghan, in the house of Hamid inb al- Hamid al-Taee al-Toosi in Pahlavi Rashid [?] ".
Imam Reza's (PBUH) migration was a mandatory political migration that happened in the year 200 AH by direct order of the caliph. The path of his journey was as follows:
2. Mecca (some scholars do not consider this city in the migration path)
7. Arjan (Behbahan)
9. Dehshir (Farashah)
11. Ghadamgah Kharaneq (Mashhadak)
14. Neyshabur Ghadamgah
During Imam Reza's migration, three main issues occurred that are respectively: His sickness in Ahvaz, People's welcoming him in Neyshabur and addressing the Silsiat al-Zahab Hadith and imprisonment in Sarakhs. Because of the the outstanding welcoming from the people of Neyshabur and stating the Silsilat al-Zahab Hadith by him, the Abbasids spread the word that Imam Reza (PBUH) has claimed divinity, and imprisoned him in Sarakhs. The time that Imam (PBUH) was in prison is not known. But this happening indicates that accepting the crown prince position was something mandatory. By Imam's entrance to Merv, Ma'mun welcomed him very warmly so that he could carry out his plans and after accepting the crown prince position by him, he minted coins bearing Imam’s name.