Editing Ali al-Rida (section)

==Debates over Position of Crown Prince==
The extraordinary decision of the caliph, which immediately aroused strong opposition, especially among the Abbasids, was widely attributed, even in Khorasan, to the influence of the Persian vizier Fazl b. Sahl. Among the later historians, this view was supported by Sallami in his Akhbar Khorasan and by Suli, who quoted the Tahirid Obaydallah b. Abdallah b. Taher as affirming that Fazl proposed the appointment to Maʾmun. In other accounts, however, the initiative is ascribed to the caliph himself and Fazl is reported to have at first resisted the appointment pointing out the grave danger of such a move. This version is clearly more in consonance with the known political views of the caliph and the vizier. 

According to some reports, the caliph made his decision in fulfillment of an earlier vow that he would turn over the caliphate to a descendant of Ali if he were granted victory over his brother Amin. In his official letter, he explained that he had found Ali al-Rida to be the most excellent and suitable candidate among the descendants of Abdallah b. Abbas and Ali b. Abi Taleb and expressed his hope that his choice would help to restore concord in the Muslim community. In his note of acceptance added to the document, Rida expressed similar sentiments, commending Maʾmun for his efforts to remedy the wrongs previously done to the Alids and promising to treat the Abbasids justly if he should succeed to the caliphate. That Fazl b. Sahl had to be reassured with respect to the caliph’s decision is indicated by the fact that Maʾmun on the same day wrote another letter lauding the vizier’s past services and granting him and his brother Hasan unrestricted powers as well as additional compensation in money, jewels, and land and the right to retire with full honors at any time he might desire.

Maʾmun evidently desired that Rida should immediately share in the rule and in all official ceremonial. Rida, however, is reported to have stipulated that he would not participate in the business of state. He was given his own police force (shorat) and guard (haras) under commanders belonging to the Khorasanian loyalists of Maʾmun as well as a chamberlain (hajeb) and a secretary (kateb). The caliph relied on his judgment in religious questions and arranged for debates between him and Muslim scholars as well as the leaders of other religious communities. At the beginning of the year 202/late summer, 817, the ties between the caliph and Rida were further strengthened as marriages were contracted between Rida and Maʾmun’s daughter Omm Habib, between Rida’s son Muhammad (who was only six years old and remained in Medina) and Maʾmun’s daughter Omm al-Fazl, and between Maʾmun and Buran, daughter of Hasan b. Sahl. 

Rida’s relations with Fazl b. Sahl apparently were never good. According to several accounts, the vizier had been hiding from Maʾmun the seriousness of the opposition in Iraq and it was Rida who opened his eyes to it and urged him to return to Baghdad in order to restore peace by his presence. Rida’s assessment of the situation being supported by several army chiefs, Maʾmun decided to leave for Iraq. Fazl b. Sahl whose aim had been to keep the capital in the east, offered his resignation, pointing out the extreme hatred of the Abbasids in Baghdad for him personally and requested the caliph to leave him as governor in Khorasan. Maʾmun again assured him of his complete trust and asked him to compose another letter in the caliph’s name confirming his exceptional privileges. The letter which affirmed the caliph’s unrestricted support of the vizier and his policy and contained the full text of the previous letter, was signed by Maʾmun in Safar, 202/August-September, 817 and, at the request of Fazl, formally confirmed by Riza. It was then sent to be published throughout the empire. Six months later, as Maʾmun slowly moved west with his court, the vizier was murdered in Sarakhs by several army officers, on 2 Shaʿban 202/12 February 818. The caliph ordered their execution, while they claimed to have acted under his order.