Nasir al-Din al-Tusi was impacted by the writings of Imam Hasan Ala Dhikrihi al-Salam

Nasir al-Din al-Tusi, one of the major intellectual scholars of the thirteenth century who contributed to many fields of learning, was born in 1201 in Tus, northeastern Persia into a Twelver Shi’i family. His father, a prominent jurist, encouraged al-Tusi to study all branches of knowledge and examine the views on the various schools of Islamic tradition, because his father “was not altogether satisfied with a purely prescriptive approach to the faith” (Badakhchani, Contemplation and Action p 1). Al-Tusi acquired an enduring thirst for knowledge, travelling far and wide in search of it.

In his autobiographical work Sayr wa suluk (‘Contemplation and Action‘), al-Tusi “gives a brief account of his intellectual growth. After mastering all the sciences of his day, from theology and philosophy to mathematics and astronomy, Tusi remained dissatisfied, feeling that he was no nearer the truth [that he had been searching for] than before. What frustrated him more than anything else was the great diversity of opinions he encountered on the most basic issues of life and faith. But there was one school of thought that he had not yet explored, and that belonged to the Ismailis.“ (Willey, Eagles Nest p 67-68).

Al-Tusi wrote
When I first embarked on [the study of] theology, I found a science which was entirely confined to practices of the exoteric side of the shari’at. Its practitioners seemed to force the intellect to promote a doctrine in which they blindly imitated their ancestors, cunningly deducing proofs and evidence for its validity, and devising excuses for the absurdities and contradictions which their doctrine necessarily entailed (SS 9).

Continuing to ponder further, al-Tusi gradually realised that “since mankind is divided in its great diversity of opinions, the attainment of the truth is not possible through intellect and reason alone but required the additional intervention of a mukammil, an agent of perfection, an authoritative instructor or preceptor who is aware of such knowledge in its very essence.” He began to inquire “into the main propagators of this doctrine, the Ismailis … ” (Badakhchani, Contemplation and Action p 3).

One day, al-Tusi came across a compilation of the Fusul-i muqaddas (‘Sacred Chapters’), the sermons and sayings of Imam Hasan Ala Dhikrihi al-Salam (d. 1166), which impacted him profoundly:

“…I occupied myself day and night at reading it, and to the extent of my humble understanding and ability, I gained endless benefits from those sacred words which are the light of hearts and the illuminator of inner thoughts. It opened a little my eye of exploration… and my inner sight… was unveiled” (SS 15).

Thereafter, my only desire was to introduce myself among the jama’at1 when the opportunity presented itself” (SS 16).

The governor of Quhistan, Naser al-Din Mohtasham, was highly learned and encouraged Tusi in his philosophical and scientific researches as a resident scholar at the fortress of Qa’in.

The castle of Qa’in. Image: Willey, Eagle’s Nest

“Among the several works Tusi produced here, the most famous is Akhlaq-e Naseri (‘The Nasirean Ethics‘), a masterly synthesis of Neoplatonic and Islamic philosophy.

A Manuscript of Akhlaq-i Nasiri created for Nasir al-Din Abd al-Rahim, Lahore, Pakistan, ca. 1590-1595. Aga Khan Museum

After ten years of scholarship at Qa’in, Tusi was invited to go to Alamut. He could now avail himself freely of the rich resources of the Alamut library and also work with other scholars under the patronage of the Imam Ala al-Din Mohammad [r. 1221-1255]. The next twenty years were the most productive of Tusi’s life, during which time he produced a large number of books on philosophy, mathematics, astronomy, and the applied sciences…. In addition to his scientific works, Tusi composed a number of specifically Ismaili works, including Rawda-yi taslim (‘Paradise of Submission‘), a comprehensive philosophical exposition of Ismaili doctrines” in 1241(Eagle’s Nest p 66-67), and Asas al-iqtibas (‘Principles of Acquisition’) in 1244.

The greatest expression of divine mercy to mankind is the appearance of the Imam of the Age
Image: The Institute of Ismaili Studies

A good portion of al-Tusi’s works produced during his association with the Ismailis has survived, whereas nothing has been preserved from, for example, the numerous writings of Imam Nur al-Din Muhammad (d. 1210) which was very popular at the time. Among other factors, the survival of Tusi’s works was undoubtedly due to the scholarly appeal of his writings, which brought him fame in his own lifetime.” (Badakhchani, Contemplation and Action p 19).

Most of al-Tusi’s works were not addressed to a specifically Ismaili audience, therefore they were likely circulated freely among the scholars of all communities before and after the fall of Alamut. “It is on the basis of these works, concerned essentially with issues and questions of interest to Muslim intellectuals in general and all those seeking knowledge, that Tusi’s considerable reputation as a scholar is founded. However, many of these works retain a certain Ismaili outlook and orientation” (Badakhchani, Contemplation and Action p 16).

Sources agree that during his long association with the Ismailis, Tusi wrote a number of Ismaili treatises that have either not survived or their Ismaili orientation may have been altered by later scholars or scribes to adapt them to the Twelver Shi’i milieu. “An example of such an amended text is Risala-yi jabr wa qadar (Treatise on Free Will and Predestination), a philosophical work in which quotations from the Fusul-i muqqadas of Imam Hasan Ala Dhikrihi al-Salam have been removed. Al-Dustur wa da’wat al-mu’minin li al-hudur (Notebook for Summoning the Faithful to the Present Imam) is another treatise which, although attributed by the compiler to Imam Ala al-Din Muhammad, is almost certainly the work of Tusi himself (Ibid).

The works of Tusi “well illustrate the significance of Ismaili intellectual and cultural life in the early decades of the 13th century, and the role of Alamut in encouraging the advancement of knowledge. As Marshall Hodgson describes it:
what was most distinctive was the high level of intellectual life. The prominent early Ismailis were commonly known as scholars, often as astronomers, and at least some later Ismailis continued the tradition. In Alamut, in Khusistan, and in Syria, at the main centres at least were libraries… which were well known among Sunni scholar… the Ismailis prized sophisticated interpretations of their own doctrines, and were also interested in every kind of knowledge which the age could offer” (Eagles Nest p 67-68).

After the Mongol conquest of Alamut in 1256, Tusi served as the scientific adviser to the Mongol leader Hulegu, who financially supported the construction of the most advanced observatory at Maragha (in present day Azerbaijan).  Tusi worked at the observatory, producing the most influential works in astronomy and mathematics, as well as Ithna’ashari theology, indicating his return to Ithna’ashari Shi’ism (The Ismailis An Illustrated History p 147).

Al-Tusi made monumental contributions to mathematics, establishing trigonometry as an independent subject. He also create the most accurate tables to calculate planetary movements to determine the position of stars and planets and referenced until Copernicus developed one 250 years later.

Nasir al-Din al-Tusi died in Baghdad in 1274. “He left an enduring intellectual legacy for Ismaili and Ithna’ashari Shi’ism as well as for all scholars of ethics, logic, mathematics, metaphysics, and theology” (The Ismailis An Illustrated History p 147).

1Literally assembly, congregation or community. In Ismaili literature, from the early Alamut period, this word is always used for the Ismaili community in particular. Contemplation and Action, Edited and translated by S.J. Badakhchani, I.B. Tauris in association with The Institute of Ismaili Studies,  London, 1999 (p 67 n 13)
Aziz Merchant, Nasir al-Din al-Tusi and Astronomy, The Institute of Ismaili Studies
Farhad Daftary, Zulfikar Hirji, The Ismailis An Illustrated HistoryAzimuth Editions in association with The Institute of Ismaili Studies
Jalal Badakhchani, Paradise of SubmissionSynopsis, The Institute of Ismaili Studies
Nasir al-Din al-Tusi, Encyclopaedia Britannica
Peter Willey, Eagle’s Nest: Ismaili Castles in Iran and Syria, I.B. Tauris in association with The Institute of Ismaili Studies, London, 2005


Nimira is an invited writer at Ismailimail, although she has contributed several articles in the past (view previous articles). She also has her own blog – Nimirasblog – where she writes short articles on Ismaili history and Muslim civilisations. When not researching and writing, Nimira volunteers at a shelter for those experiencing homelessness, and at a women’s shelter. She can be reached at

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