Ali al-Rida, Abu’L-Hasan B. Musa B. Jaʿfar (d. 203/ 818), is the eighth Imam of the Imami Shiʿites. In Shiʿite sources he is commonly referred to as Abu’l-Hasan al-Thani in order to distinguish him from his father, Imam Musa al-Kazem, who is known as Abu’l-Hasan al-Awwal. He was born and grew up in Medina. The year of his birth is variously given as 148/765, 151/768, and 153/770. The first date appears least reliable and may have been deduced from a prediction ascribed to his grandfather, who died in that year, that the successor to his son Musa would be born soon. There are indications that Ali may have been born as late as 159/775-76, since, according to Yaʿqubi, he died at the age of forty-four and, according to Waqedi, he began rendering fatwas in his twenties. His mother, whose name is variously given as Toktam, Najma, Shaqraʾ, Shahd, Omm-al-banin, Khayzoran, Sakan, Arwa, or Samman, was probably of Nubian origin.
His father, Imam Musa al-Kazem, who died in prison in Baghdad in Rajab, 183/September, 799, made him his legatee, and Ali inherited his estate of Sorayyaʾ near Medina to the exclusion of his many brothers. But the death of Imam Musa was denied by several of his wakils; they withheld the money collected from the Khoms and vows of Imam Musa’s followers and refused to recognize Ali as Imam, promising the return of his father as the Mahdi. This led to a large-scale defection from the ranks of his father’s followers, especially in Kufa and Baghdad; Ali was later accused by them of diverging from the teaching of his ancestors in some points. Of his brothers, none seems to have claimed the imamate for himself, though some apparently furthered the belief in the survival of their father. According to Waqedi, he transmitted Hadith from his father and his uncles and gave fatwas in the mosque of Medina. Though Waqedi describes him as a reliable transmitter (theqa), he was evidently shunned by Sunni traditionists in Medina, and his transmitters were strictly Shiʿite. There is no good evidence that he ever left Medina for an extended trip before his departure for Khorasan, though a Shiʿite report describes a miraculous visit by him to the communities of his followers in Basra and Kufa after the death of his father. Several of his brothers and his uncle Muhammad b. Jaʿfar participated in the Alid revolts in Iraq and Arabia after the death of the caliph Amin, but he refused any involvement.
Journey to KhorasanEdit
In 200/815-16, the caliph Maʾmun wrote inviting him to come to Marv and sent Rajaʾ b. Abi’l-Zahhak, cousin of the vizier Fazl b. Sahl, and the eunuch Fernas to accompany him on his trip. Shiʿite sources name in place of Fernas the eunuch Yaser, who later appears in the personal service of the Imam and, after the latter’s death, reported about him in Qom. The assertion by Abu’l-Faraj Esfahani and Mofid that the Imam was accompanied to Marv by the general Isa Joludi is definitely mistaken. The latter in this year suppressed the rebellion of Muhammad b. Jaʿfar in Mecca and took him along to Iraq, where he was surrendered to Rajaʾ b. Abi’l-Zahhak.
Rajaʾ thus conveyed both Alids to Khorasan. The Imam seems to have made the pilgrimage to Mecca in this year accompanied by his five-year-old son Muhammad. He set out for Marv early in 201/late summer, 816. His travel route was, according to most sources, via Basra, Ahvaz, and Fars; this was natural since Baghdad and Kufa at this time were in the hands of rebels. Yaʿqubi’s statement that Rajaʾ traveled via Baghdad and Nehavand (Mah al-Basra) is thus erroneous. It is certain that the Imam did not pass through Qom. He visited Nishapur, where the prominent Sunni traditionists like Ebn Rahuya, Yahya b. Yahya, Muhammad b. Rafeʿ, and Ahmad b. Harb came out to meet him, and he stayed for some time in the town. Shiʿite sources report that next to the house where he stayed he planted an almond tree whose fruit had miraculous healing power. A bath in the quarter of his residence was known in the time of Ebn Babuya as Ḥammam al-Rida and people used to come to wash in and drink from a spring there where he had washed himself and prayed.
On a new summons of Maʾmun, the Imam continued on to Marv. According to some Shiʿite accounts, Maʾmun at first proposed to resign from the caliphate in favor of him. The Imam resisted his proposals for about two months but finally consented reluctantly to an appointment as heir to the caliphate. Maʾmun gave him the title Reza, which had previously been used in Shiʿite rebellions to refer to the descendant of the Prophet upon whose choice as caliph the Muslim community would agree. Shiʿite claims that the name had been given to him by his father appear to be without foundation. The bayʿa of the dignitaries and army leaders in Marv to the heir-apparent took place according to Tabari on 2 Ramazan 201/23 March 817, according to Suli on 5 Ramazan/27 March. The first to pledge allegiance to Reza, who was dressed in green, was Maʾmun’s still minor son Abbas. Among the poets who offered their eulogies to him on this occasion were Ebrahim b. Abbas Suli and Deʿbel Khozaʿi. Both wore given 10,000 of the newly minted dirhams bearing the name of the Alid. Abbasids and Alids then took turns in receiving gifts, the former led by Abbas b. Maʾmun, the latter by Muhammad b. Jaʿfar. After the ceremony, on 7 Ramazan/30 March, an official letter of the caliph announcing the appointment was drawn up to be read in the mosques throughout the empire. Maʾmun gave orders that the name of the crown prince be included in the Khutba everywhere and that the color of the uniforms, official dress, and flags be changed from black, the official Abbasid color, to green. The color green had not previously been associated with the Alids and was probably intended to signify a reconciliation between Abbasids and Alids rather than a surrender to the claims of the latter.
Debates over Position of Crown PrinceEdit
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.
When the Carvan reached Ṭus, Rida fell ill and died after a few days, according to the most reliable accounts on the last day of Safar, 203/September 818. Other dates mentioned range from Safar, 202/September, 817 to Dhu’l-qaʿda, 203/May, 819. The caliph asked a group of Alid relatives of Rida, including his uncle Muhammad b. Jaʿfar, to examine his body in order to have their testimony that he had died a natural death and ordered that he be buried next to the tomb of his own father, Harun al-Rashid, in the house of Homayd b. Qahtaba in Sanabad near Nawqan. He displayed extreme grief and is reported to have walked bareheaded in the funeral procession and to have stayed on the grave for three days. Nevertheless, most of the sources charge him with having poisoned Rida. The sudden demise of both the vizier and the heir-apparent, whose presence would have made any reconciliation with the powerful Abbasid opposition in Baghdad virtually impossible, must indeed arouse strong suspicion that Maʾmun had had a hand in the deaths.
Imami tradition ascribes to Imam Ali al-Rida numerous miracles demonstrating his foreknowledge of deaths and other events, his ability to read the minds of his visitors, to interpret dreams, and to strike bars of gold out of the earth, his healing power, his knowledge of all human and animal languages, and the fulfillment of his prayers.
Several short works are attributed to him:
Al-Resalat al-dhahabiya (or al-modahhaba) fi’l-tebb is a treatise on medical cures and the maintenance of good health which is said to have been written for the caliph Mansur at his request.  It was named “the golden treatise” because Maʾmun ordered it to be written with gold ink. Among the Imami bibliographers of the 5th/11th century it was known through the initial transmission of Muhammad b. Hasan b. Jomhur ʿAmmi, a Basran Imami transmitter considered unreliable and extremist. A number of commentaries have been written to it and it has been translated into Persian and Urdu.
Sahifat al-Rida is a collection of 240 Hadiths initially transmitted by Abdallah b. Ahmad b. Amer from his father Ahmad, who stated to have heard it from Rida in 194/809-10. Abdallah b. Ahmad b. Amer is mentioned by Najashias the transmitter of a noskha from Rida.
This book was unknown among Imami scholars until the 10th/16th century, when a group of scholars from Qom brought a copy of it containing numerous ejazas to Mecca. It was judged to be authentic by the two Majlesis but later Imami scholars were divided about it, the majority considering its authenticity as doubtful. It has been convincingly argued by S.H. Sadr that the greater part of the book is taken from the otherwise lost Ketab al-taklif of the Imami heretic Muhammad b. Ali Shalmagani.  Other works attributed to Rida are listed in Aʿyan al-Shiʿa.  Shiʿite sources also contain detailed description of his debates on religious questions and quotations of his sayings and his poetry.
- Tabari, III, pp. 993-95.
- text edited in Bombay and fully quoted in Majlesi, Behar al-anwar LXII, pp. 308-28.
- d. 322/934; see his “Fasl al-qazaʾ fi’l-Ketab al-moshtahar be Feqh al-Rida,” in Ashnayi ba Chand noskha-ye khatti I, Qom, 1396/1976, pp. 389-442.
- IV/2, pp. 180ff., and Sezgin, GASI, p. 536.
- See also Ḵalifa b. khayyaṭ, Taʾrikh, ed., A. Ziaʾ Omari, Baghdad, 1386/1967, pp. 508ff.
- Ebn Habib, Asmaʾ al-moghtalin, ed. ʿA. Harun, in Nawader al-makhtutat, 2nd ed., Cairo, 1393/1973, II, pp. 201f.
- Yaʿqubi, II, pp. 544f., 550f.
- Nawbaḵtī, Feraq al-shiʿa, ed. H. Ritter, Istanbul, 1931, pp. 67-74.
- Tabari, III, pp. 1000, 1012ff., 1025ff., 1029ff.
- Kolayni, al-Kafi, ed. ʿA. A. Ghaffari, Tehran, 1381/1961, I, pp. 311-19, 486-92.
- Masʿudi, Moruj II, pp. 3, 59-62.
- Idem, Tanbih, pp. 349ff.
- Abu’l-Faraj Esfahani, Maqatel al-Talebiyin, ed. A. Ṣaqr, Cairo, 1368/1948-49, pp. 561-72.
- Aghani1 IX, pp. 25ff.; XVIII, pp. 29, 42ff.
- Balʿami, Chronique IV, pp. 508-18.
- Ebn Babuya, Oyun Akhbar al-Reza, ed. M. Ḥ. Akhundi, Qom, 1377/1957-58.
- Mofid, al-Ershad, ed. K. Musawi Miamavi, Tehran, 1377/1957-58, pp. 284-96.
- Samʿani (Hyderabad), VI, pp. 139ff.
- Ebn al-Jawzi, Tadhkerat al-khawass, Najaf, 1383/1963-64, pp. 351-58.
- Ebn Ḵallekan (Beirut) III, pp. 269-71.
- Erbeli, Kashf al-ḡomma, ed. E. Mianji, Tabriz, 1381/1961-62, III, pp. 70-184.
- Ebn Hajar, Tahdhib al-tahdhib, Hyderabad, 1325-27/1907-09, VII, pp. 387-89.
- Majlesi, Behar al-anwar, Tehran, 1956-, XXXIX.
- F. Gabrieli, Al-Maʾmun e gli ʿAlidi, Leipzig, 1929, pp. 35ff.
- D. M. Donaldson, The Shiite Religion, London, 1933, pp. 161-69.
- H. E. Hasan, “al-Maʾmun wa-Ali al-Reza,” Majallat kolliyat al-adab, Cairo, 1, 1933, pp. 84-94.
- Aʿyan al-shiʿa IV/2, pp. 77-214.
- D. Sourdel, “La politique religieuse du Calife Abbaside al-Maʾmun,” REI 30, 1962, pp. 33ff.
- W. Madelung, “New Documents concerning al-Maʾmun, al-Faḍl b. Sahl and Ali al-Riḍa,” in Studia Arabica et Islamica: Festschrift for Ihsan Abbas, ed. W. al-Qadi, Beirut, 1981, pp. 333-46.