Abu Ya'qub Ishaq ibn Ahmad al-Sijistani () or al-Sijzi () was a 10th-century Persian Ismaili missionary active in the northern and eastern Iranian lands. His life is obscure, but he was a prolific writer, who played a crucial role in the infusion of Neoplatonic ideas into Isma'ili theology.

Life
Al-Sijistani's life is obscure, as references to him are found mostly in isolation in hostile Sunni heresiological works, while Isma'ili sources usually do not provide any details about him. He was given the nickname 'cottonseed' (Arabic: , Persian: ) in several near-contemporary non-Isma'ili works that mention him, but the origin and significance of it are unknown. What can be gleaned from the sources is that he was a senior missionary () in the Iranian lands of the eastern Islamic world.
 
Nizam al-Mulk reports that a certain Ishaq succeeded Abu Hatim al-Razi as chief  at Rayy upon the latter's death on 934, while Ibn al-Nadim mentions a certain Abu Ya'qub as the chief  at Rayy in . This Abu Ya'qub was also in charge of the missionary movement () in Upper Mesopotamia and Iraq, with the brothers Abu Muslim and Abu Bakr ibn hammad in Mosul and Ibn Nafis in Baghdad as his agents. This is likely to have been the same person as al-Sijistani, as it agrees with a statement in one of al-Sijistani's works that he was in Iraq in 934. Earlier opinion among scholars was that he was executed along with Muhammad al-Nasafi in 943, but this is now disproven. In reality, he was al-Nasafi's successor, both as chief  in Khurasan, as well as in continuing the development of al-Nasafi's theological ideas. Other sources maintain that he was active in Sijistan (whence his ), both during and after al-Nasafi's tenure.

The movement he headed was not initially affiliated with the Fatimid Caliphate, but at some point, during the caliphate of al-Mu'izz li-Din Allah (), he accepted the Fatimids as the legitimate imams, and many of his views were taken over by the Fatimid-sponsored . According to Rashid al-Din Hamadani, al-Sijistani was executed by the Saffarid emir of Sijistan, Khalaf ibn Ahmad (). Al-Sijistani's work Kitāb al-iftikhār was written around 971, this provides a terminus post quem for his execution. The introductions to two of his other works indicate they were written during the reign of the Fatimid caliph al-Hakim bi-Amr Allah (), but they are likely later interpolations. Al-Sijistani died in 971.

Works
Several of al-Sijistani's works survive, having been copied and studied by the Tayyibi Isma'ili communities of Yemen and India. However, as they are regarded as "highly esoteric and restricted", they have been slow to be studied by modern scholars and published in critical editions. Furthermore, as the historian Paul Walker comments, "[a]s they exist now, it is in some cases difficult to determine the original form of the texts", as many survive only in translations or paraphrased summaries. Some works are only known by title or in fragments, being cited or quoted in other works.

Kashf al-mahjub
The  ('Unveiling of the Concealed'), was the first of al-Sijistani's works to become available to scholars. It only survives in a Persian translation, or even paraphrase, of the Arabic original, produced in the 11th century. It comprises seven chapters, each further divided into seven parts. The aim of the work is to 'unveil' divine knowledge (, ), and deals with the concepts of the Oneness of God (), the stages of creation, the nature of prophethood, and resurrection (). Based on its containing passages supporting the idea of metempsychosis, it likely belongs to the early phase of al-Sijistani's career, before he accepted Fatimid orthodoxy. 

Excerpts of the work were first published by Mahdi Bayani in 1938 (, Tehran, Shirkat-i Chāp-i Khudkār). The Persian text was published with a French commentary in 1949 by Henry Corbin (Tehran, Institut Franco-Iranien & Paris, A. Maisonneuve). Corbin also published a full French translation in 1988 as  (Lagrasse, Verdier). A partial English translation was published by Hermann Landolt (Kashf al-maḥjūb, Unveiling of the Hidden) in S.H. Nasr and M. Aminrazavi (eds.), An Anthology of Philosophy in Persia, Volume II (Oxford,  Oxford University Press, 2001).

Ithbat al-nubu'at
The  or  ('Proofs of Prophecies'). In its seven sections, al-Sijistani "puts forward a variety of proofs for the necessity of prophecy (), also explaining different prophetic eras". According to Paul Walker, it shows signs of later editing, and all available manuscripts are missing the final two sections.

The work was published in Arabic in 1966 by Arif Tamir (Beirut, al-Matba'a al-Kathulikiyya). According to Walker, this edition "contains errors, faulty readings, pages out of order, and extraneous passages".

Kitab al-iftikhar
The  ('The Book of Boasting'), is likely the last of al-Sijistani's works, being written around 971. As its title suggests, it is "strikingly polemical and strikingly defensive and apologetic" work; Walker describes it as "an exceedingly frank confession of the points of difference between himself and the Ismaili , on the one hand, and the intellectual, religious world all around him, on the other". For Walker, it is perhaps the "[best] place to look for a definition of [Isma'ili Shiism] in its fourth / tenth-century manifestation", while Farhad Daftary, points out that it "presents a summary exposition of Ismaili doctrine and preserves remnants of the mythological cosmology propounded by the early Ismailis, including the spiritual beings called ,  and  which mediated between the spiritual and the physical worlds".

The work was first partially published by Mustafa Ghalib in 1980 (Beirut, Dar al-Andalus), but "suffers from inaccuracies and serious omissions". In 2000 a "definitive" edition with an English commentary was published by Ismail K. Poonawala (Beirut, Dar al-Gharb al-Islami).

Al-Yanabi
The  ('Book of the Wellsprings/Sources [of Wisdom]'), was written around 961, and extensively paraphrased by the 11th-century  Nasir Khusraw in his own  . The work is a collection of treatises on about forty themes or 'wellsprings'. According to Daftary, the work's primary theme is "the wellsprings of human knowledge and spiritual life in each era of religious history", while Walker emphasizes that "portions of this work are purely Neoplatonic in the tone and in the content of its teachings; other sections bring these concepts in line with the author's Shiite interpretation of religious knowledge and its purveyors".

The work was first published in a critical edition, with a partial French translation () in Henry Corbin's 1961 Trilogie Ismailienne (Tehran, Département d’Iranologie de l’Institut Franco-Iranien and Paris, A. Maisonneuve). An Arabic edition was published by Mustafa Ghalib in 1965 (Beirut, al-Maktab al-Tijari), and an English translation by Paul Walker in 1994 as part of The Wellsprings of Wisdom: A Study of Abu Yaqub al-Sijistani's Kitab al-Yanabi (Salt Lake City, University of Utah Press).

Al-Maqalid
The  ('Book of the Keys'), comprises seventy chapters. According to Walker, it is of exceptional importance as it is "relatively late and by any account the most comprehensive" of al-Sijistani's works, but remains unpublished.

Al-Nusra
The  ('Book of the Support/Defence'), is no longer extant, except for extensive quotations in Hamid al-Din al-Kirmani's . The work is one of al-Sijistani's earlier writings, composed as a defence of his predecessor and teacher, Muhammad al-Nasafi, against the accusations of antinomianism by Abu Hatim Ahmad ibn Hamdan al-Razi.

Sullam al-najat
The  ('Ladder of Salvation') survives only in an incomplete form. In it, al-Sijistani gives a summary of the Isma'ili doctrine (). According to Walker, these can be summarized as "faith in God, His angels, His books, His emissaries, the last day, salvation after death, and paradise and hellfire".

Its Arabic text was published by Muhtadi Mustafa Ghalib in 2002 (Salamiyya, Dar al-Ghadir). An English translation is part of a 1983 doctoral dissertation by M. Alibhai (Abu Ya'qub al-Sijistānī and Kitab Sullam al-Najāt: A Study in Islamic Neoplatonism, Harvard University).

Epistles
The epistle  expounding on Isma'ili doctrine was published by Arif Tamir in  and reprinted since in  in March/April 1967, and in Tamir's .

The epistle  was published by Boustan Hirji in 1992 (, Vol. 7), with a Persian-language translation by Abdallah Nurani. An English-language translation was published as part of B. Hirji's doctoral thesis A Study of al-Risālah al-Bāhirah (McGill University, 1994).

References

Sources

External links
 Abu Ya‘qub al-Sijistani at the Internet Encyclopedia of Philosophy

10th-century executions
10th-century Iranian philosophers
10th-century Ismailis
Neoplatonists
Year of birth unknown
Year of death unknown
Iranian Ismailis
Executed Iranian people
Ismaili theologians
Ismaili da'is