The works of Nasir al-Din al-Tusi have always attracted the interest of Ottoman scholars as early as the 14th century. Some of his works were translated into Turkish and various annotations or commentaries were written upon them. They were also introduced in the school curriculum as textbooks, which testify to the wide scope of his impact on Ottoman scholarship. Another aspect of his remarkable influence is represented by the presence of very numerous manuscript copies of al-Tusi's works in many libraries of Turkey, especially Istanbul, and in many countries previously governed by the Ottomans. This article examines al-Tusi's work on scientific fields practiced under the Ottomans such as mathematics, astronomy, scientific instrumentation, and mineralogy and demonstrates how important he was to the scholarship of the Ottoman world.
Dr. Salim Ayduz*
Table of contents
3.1.2. Commentaries on ‘Si Fasl’ during the Ottoman Period
3.1.2. Turkish Translations of Si Fasl
3.2.2. Commentaries on Tahrir Usul al-Handasa
3.3.1. Commentaries on Bist bab
3.3.2. Translations of Bist Bab
3.4.1. Commentaries during the Ottoman Period
3. 5. Tansuq-nama-yi Ilhani
3. 6. Tahrir al-Majisti
Nasir al-Din Abu Ja’far Mu?ammad ibn Mu?ammad ibn al-?asan Muhammad ibn Muhammad b. Hasan Abu Bakr al-Tusi (1201–1273/74) was a polymath scholar of science and philosophy who wrote many books in diverse areas of learning such as astronomy, mathematics, medicine, music, logic, physiology, philosophy, literature, geography, theology and occult sciences. He also founded and directed the famous Maragha observatory, one of the largest astronomical observatories in the Islamic world .
Nasir al-Din al-Tusi was born in 1201 in the city of Tus. He spent his childhood and early youth in Tus, and received his primary education from his father. He learnt mathematics from a well-known scholar of the era, Kamal al-Din Muhammad Hasib, and received his logarithm, logic, philosophy and cognition tuition from Abul-?asan Bahmanyar ibn Marzuban ‘Ajami Adarbayijani (d. 1067) who was an Azerbaijani scholar and also Ibn Sîna’s student. We have the impression that he was a passionate, freethinking researcher with an expansive wisdom, wide imagination and a sharp memory even at a young age.
After completing his education, Nasir al-Din al-Tusi arrived in Kuhistan at the invitation of Nasir Muhtasham, the Ismaili governor, and gained a great deal of respect amongst the Ismailis, also influencing them with his ideas. However, their relationship soured with time, and Nasir al-Din al-Tusi was then kept under surveillance in the castle of Alamut under the control of the Ismaili’s for twenty-two years. There, despite his harsh living conditions, he produced his most important works on astronomy, philosophy, logic and related areas of science.
In 1256 when the Ismaili’s were defeated by Hulagu, Nasir al-Din al-Tusi regained his freedom and became advisor to the Moghol ruler. In 1258, he obtained permission from Hulagu to build the Maragha observatory and began to make observations there after its completion in 1259. Nasir al-Din al-Tusi remained in his position during the regency of Abaka Khan, Hulagu’s successor, and died in Bagdad in 1274 . He was a great figure in the Islamic scientific tradition and a key contributor to both political and intellectual life during a century that witnessed enormous changes in the world.
Nasir al-Din al-Tusi was one of the most prolific authors of the Islamic medieval period, writing in both Persian and Arabic, over 150 works (excluding his poetry). He wrote on both religious and secular topics. He was a well-recognised scholar in the Ottoman world, as well as other parts of the Islamic world. The fact that al-Tusi held an important place in the Ottoman scientific literature is well understood from the fact that his books were introduced into the madrasas as textbooks and numerous copies were kept in many Ottoman libraries .
Furthermore, his works were utilised and translated into Turkish by many Ottoman scholars from the time of the formation of the Empire. His works including annotations were copied and translated, and several works based upon them were produced. In addition to Nasir al-Din al-Tusi’s actual written legacy, some observational tools that he had developed in the Maragha Observatory were also been copied and revised by Taqi al-Din Rasid in Istanbul in the late 16th century . This shows that al-Tusi was not only influential in the literature of the Ottoman world, but also in developing astronomical devices.
In addition to commentaries and translations of al-Tusi’s works, direct copies of them were made, including copies of the so-called “Middle-books” or Mutawassitat, a collection of various works redacted by al-Tusi in astronomy, mechanics and music . One such copy was produced at the request of the Ottoman Sultan Muhammad II in 1477–1478 .
In short, it can be said that the source of works that influenced the Ottoman astronomy and that comprised Ottoman astronomical literature are the works of scholars who were members of the Maragha, the Samarkand and the Egyptian astronomy-mathematic schools. Amongst these are the important works of Nasir al-Din al-Tusi, the head of the Maragha School. Some of the works that we will be discussing in this paper are Zij Ilhani, al-Tadhkirat al-Nasiriyya, Si Fasl, Bist Bab and Tahrir al-Majisti.
The title of this treatise, which was written initially in Persian, namely Si Fasl dar Ma’rifat-i Taqwim (Thirty Chapters on the Knowledge of the Calendar) show clearly its subject and purpose .
This is also known as Risala-i Si Fasl. As one can guess from the title, this work is made up of thirty chapters and is one of the most famous and widely known works of Nasir al-Din al-Tusi on calendar making. This work was written in the State of Assassins. The treatise chapters concern the following topics: 1) on literal numeration, 2-6) on calendars and eras including Jalali calendar of Khayyam (1048–1131), 7-16) on the Sun, the Moon, and the planets, 17-30) on astrological problems.
The book was translated into Turkish by Ahmed-i Dai of Germiyan  (d. after 1421). It was used by Ottoman scholars in the madrasas as a textbook on astronomy and especially on calendar making. The number of annotations from both the pre and post Ottoman era and the relatively high number of translations made during the Ottoman era indicates how commonly and frequently it was used. Twenty-six copies of this book are being displayed in various libraries throughout Turkey. Ibrahim Hakki of Erzurum also mentions Tartib al-Ulum in his book Ma’rifatnama. These citations show how common this work was at madrasas in the 18th century. Between 1649 and 1650, similarly, Hajji Khalifa advised his students to read Si Fasl .
3.1.2. Commentaries on ‘Si Fasl’ during the Ottoman Period
a. Sharhu Si Fasl (in Arabic), written by ‘Abd al-Wacid b. Muhammad al-Kutahi (d. 1435); it was translated later on into Turkish by Ahmed-i Raci .
b. Muvadhdhih al-Rusum fi ‘ilm al-Nujum (in Persian), with a commentary by Dellakoglu (d. 1495) in 1478 and dedicated to Sultan Muhammad II (1451-1481) .
c. Mukhtasar dar Ma’rifat Taqwim (in Persian), written by Hizir-Shah al-Mantashavi (d. 1449) .
3.1.2. Turkish Translations of Si Fasl
A. Tarjama-i Si Fasl : Translated by Ahmed-i Dai of Germiyan . A note in the introduction to the book shows that it was a textbook in the Ottoman madrasas . In the introduction, Ahmed-i Dai said that he dedicated the translation to Sultan Celebi Muhammad . There are two different editions of this translation . I. H. Ertaylan first published the translation of the book with Turkish transliteration as Eskâl-i Nâsir-i Tûsî Tercümesi (Istanbul 1952). Later on, it was published again by Muammer Dizer and T. N. Gencan with Turkish transliteration, footnotes and explanations .
B. Tarjama-i Mukhtasar dar Ma’rifat-i Taqwim: A translation of Nasir al-Din al-Tusi’s book on calendar making. Since it has seven chapters, it might be an abridged version of Si Fasl. It is the first book on calendar making during the Ottomans period. The only copy of the book contains the year 1397 .
C. Tarjama-i Sharh-i Si Fasl . The Turkish translation of Abd al-Wacid Kutahi’s (d. 1435) commentary on Si Fasl (Sharh Si Fasl). It was translated by Ahmed-i Raci (c. 1621) with the encouragement of Grand Vizier Sokullu Mehmed Pasha’s son Grand Vizier Ibrahim Pasha (d. 1622) .
In the Ottoman world, al-Tusi’s tables were also extensively used for calendar making and other activities related to astronomy and astrology. In the book Istikhraj Dustur by Osman Efendizade Abdullah Efendi (d. 1780) for instance, there are ru’yat al-ahilla’s (crescents observation) tables for the year 1754–55 according to al-Tusi’s tables for Istanbul’s longitude .
This famous book is a very important teatise of the Arabic Euclidean tradition of geometry. It is the recension (tahrir) in Arabic by Al-Tusi of the Elements of Euclid. Known in general under the title Tahrir Kitab usul al-Handasa li-Uqlidis (Recension of the Book “Elements of Geometry” of Euclid), it had also the following title in some copies: Tahrir Uqlidis fi ‘ilm al-Handasa (Recension or Exposition of Euclid on the Science of Geometry”) .
Euclid’s’ Elements (Kitab al-Usul) was extensively used and commentaries made on it in the Islamic world. Among them Nasir al-Din al-Tusi’s commentary Tahrir Usul al-Handasa completed in 1248 is the most successful and valuable work focussing on Euclidean geometry .
According to Seyyed Hossein Nasr, Nasir al-Din al-Tusi’s Tahrir and the commentaries of al-Sayyid al-Sharif al-Jurjani were used since the 13th century as the main course book for geometry lessons among the madrasa students in both the Islamic world and the Ottoman State .
Kawakib-i Sab’a reports that students were taught Euclid’s’ Book ranking at istiksâ, after Sharhu Ashkâl al-Ta’sis ranking at iktisar. Here, what is meant by “Euclid’s’ Book” is Tahrir Usul al-Handasa .
In the geometry section of his De La Littérature des Turcs, Abbé Toderini provides the following information on the Ottoman teaching of geometry:
“Geometry falls under the group of Turkish studies. In academies (madrasa), there are professors (mudarris) for teaching it [geometry] to young people. The time period between mathematics and rhetoric classes is allocated to this mathematical branch… This science is taught in a special manner. I have been to the Valide Madrasa twice, during which time students had gathered to listen to the geometry class. They used an Arabic translation of Euclid. There are many versions as well as commentaries of this book. Nasir al-Din et-Tusi’s commentary, which is regarded as the best of these, has already become popular thanks to the Medicis Publishing House. This copy contains a copy of the Turkish license granted by Sultan Murad III (1574-1595) in Istanbul in 1587 . “He has granted permission for the sale of this book without any tax or liability within the entire Ottoman territory…” .
Figure 1: Sultan Murad III’s firman about al-Tusi’s book Tahrir Kitab usul al-Handasa li-Uqlidis printed in Italy in 1594.
There are also other records which show that the Tahrir Usul al-Handasa was used at Ottoman madrasas. For example Munajjimbashi Mustafa Zeki al-Istanbuli (d. 1739) was tutored with this book in 1712 by La’lizade ‘Abdülbaki b. Muhammad b. Ibrâhim (d. 1746); Yanyali As’ad Efendi with Usul-i Uqlidis by Müneccimek Muhammad Efendi; and Hasan al-Jabarti at his home (d. 1774) with Tahrir Uqlidis by Husam al-Din al-Hindi in 1731 .
3.2.2. Commentaries on Tahrir Usul al-Handasa
Hajji Khalifa reports that the Ottomans scholars Al-Sayyid al-Sharif and Kadizade-i Rumi had written one commentary each on Tahrir Usul al-Handasa, and that Kadizade’s commentary went as far as the seventh treatise .
During the Ottoman period, the first study on the Tahrir is Ilhaku Abu Ishaq by Abu Ishaq Abdullah al-Kirmani (15th century). This work meticulously annotates the first four treatises of the Tahrir .
Another study on the Tahrir is the Ta’lik of the chief astronomer Munajjimbashi Darwish Ahmed Dede b. Lütfullah (d. 1702) titled Tahrir al-Fawa’id (in Arabic). It is referred to as Ta’likat ‘ala Uqlidis (Notes on Euclid) in some sources .
An additional work on the Tahrir is the Sharh Ba’d al-Makalat al-Uklidisiyya (in Arabic) by Bedruddin Muhammad b. As’ad b. Ali b. ‘Osman b. Mustafa al-Yanyavi al-Islamboli (d. 1733), son of Yanyali As’ad Efendi . However, this work is not covered in the literature. Containing some problems on Euclidian geometry, this book is one of the most important works on Euclidian geometry produced during the Ottoman period .
Figure 2: First pages of Bist bab dar ma’rifat-i asturlab, Istanbul, Suleymaniye Library, Ayasofya, MS 2620.
This work of Nasir al-Din al-Tusi in the field of the astrolabe is one of the books most used, studied and taught in Ottoman madrasas . It is titled Risala-i bist bab dar ma’rifet-i asturlab (in Persian), that is Treatise in Twenty Chapters on the Knowledge of the Astrolabe) . There are fifty-two copies of this book in Turkish libraries. Erzurumlu Ibrahim Hakki recommended this book to madrasa students by saying “regard the astrolabe as one of the applied sciences / Fly with Bist Bab to watch the solar system” in his Tartib-i Ulum. The book was taught by Hajji Khalifa many times to students between 1649 and 1650.
3.3.1. Commentaries on Bist bab
a. Sharh-i bist bab dar ma’rifat-i asturlab (in Persian): This commentary was written by Muhammad b. Haci b. Suleyman al-Bursavi (d. c. 1495) also known as Efezade, and presented to Sultan Bayezid II (1481-1512) .
b. Sharh-i bist bab dar ma’rifat-i asturlab (in Persian): Authored in Persian by al-Birjandi in 1494, this work was taught at madrasas. There are around 30 copies of it .
3.3.2. Translations of Bist Bab
A. Tarjama-i bist bab (in Turkish): This was translated into Turkish by an anonymous translator who explains in the introduction that the translation was done for Ayaz Aga, one of the entourage of the sultan of the time. This person is probably Ayaz Pasha, who served as Janissary Aga and Grand Vizier in the time of Yavuz Sultan Selim and Suleiman the Magnificent .
B. Nuzhat al-Tullab fi ‘ilm al-asturlab (in Arabic): Translated by Haydar b. ‘Abdurrahman al-Husayni al-Jazari (d. c. 1689) from Persian into Arabic, there are currently forty three copies of this book .
C. Risala-i fi ma’rifet-i sihhat al-Asturlab (in Arabic): The chapters on whether the astrolabe was built with accurately, and showing of fixed stars on the orbit of the spider, it was translated in 1716 by an unknown person .
Bist Bab was also partly translated. For example, Ibrahim b. Halil al-Erzurumi al-Haddadi, also known as “Yekdest,” translated into Turkish the section on “Signs of Twenty Seven Stars” at the end of Bist Bab .
Figure 3: First pages of Sharh-i bist bab dar ma’rifet-i asturlab, Istanbul, Süleymaniye Library, Ayasofya, MS 2641.
Nasir al-Din al-Tusi’s Al-Tadhkira fi ‘ilm al-hay’a (Memoir on the Science of Astronomy)  (in Arabic) is one of the most original and influential Arabic works in astronomy. It is a text devoted to disclose the general principles of astronomy for the general reader, whence its title as Tadhkira (Memoir). The treatise described Ptolemaic concepts such as the epicycle theory and introduced new planetary models. Al-Tadhkira is one of the two books which the Samarkand school of mathematics/astronomy studied, read, taught, discussed and commented on the most. It is placed at the heart within the Islamic astronomical tradition. At the same time, it was also taught as a textbook at Samarkand Madrasa .
Used in the Ottoman world as an astronomy textbook at the madrasas, this book of al-Tusi consisted of four chapters. Having many commentaries, the most famous of which in the Muslim world is that of al-Birjandi. The book has kept its popularity until today. It too was taught at Iranian madrasas. A commentary on Al-Tadhkira was produced on by its author under the name Tavdhih Al-Tadhkira.
While Taskoprülüzade also places this work in the group of compendia, Hajji Khalifa places it under the heading Al-Tadhkirat al-Nasiriyya fi al-hay’a, explaining that it is a compendium containing issues and certain findings of astronomy. Twenty copies are found in Turkish libraries.
3.4.1. Commentaries during the Ottoman Period
We learn from the commentaries that this work by Nasir al-Din al-Tusi was respected as a textbook and taught at Ottoman madrasas:
a. Sharh Al-Tadhkira fi al-hay’a  (in Arabic): Fathullah Shirwani (d. 1486) first wrote commentaries on the works of his mentor and then penned some additional commentaries on the important theoretical work of Nasir al-Din al-Tusi (d. 1273) on astronomical history, Al-Tadhkira fi ilm al-hay’a. Making use of commentaries previously written by al-Sayyid al-Sharif al-Jurjani and Nizam al-Din al-A’raj al-Nishaburi, Shirwani wrote this commentary completed in 1475, to build on these previous works and to offer a complete textbook to his students . Some chapters of this book tell the reader about the Ulugh Bey Madrasa and his own student years there. The 54-page appendix following the first chapter is like an individual book on optics.
b. Sharh-i al-Tadhkira-i Haja Nasir-i Tusi (in Persian) was authored by al-Birjandi in 1507 .
c. Sharh al-Tadhkira al-Nasiriyye fi al-hay’a (in Arabic): Belongs to Kadizade Rumi .
One of the books most widely used in mineralogy was Tansugname-i Ilhani or Jawahir-nama (Book on Precious Stones) of Nasir al-Din al-Tusi . Al-Tusi wrote this book in Persian in Maragha and dedicated it to Hulagu Han . It was known and used in the Ottoman world from the earliest period. Taskoprülüzade Ahmed Efendi pointed out the importance of this work describing it as “the most useful and compact text on mineralogy” . Hajji Khalifa, who referred to it as Tansugname-i ilhani, said that “it belongs to Nasir al-Din Muhammad b. Muhammad al-Tusi. It is a compendium. It is organized into four treatises; on minerals, precious stones, ores, and fragrant plants” .
This work was translated by Mustafa b. Seydi  (15th century) for Beylerbeyi Karacabey in the time of Sultan Murad II (1421–1451)  with the title Tarjama-i Tansugname-i Ilhani or Jawahirnama-i Sultan Muradi . On the cover of the translation, the title of the book is Tarjama-i Kitab al-Jawahir al-Musamma bi-Tansikh-i Ilhani . It is a reorganized and abridged adaptation of Tansugname-i Ilhani. Mutarjim Mustafa ibn Saydi removed the First, Third and Fourth treatises of the original text, and only included the Second treatise which dwells on the characteristics of mineral ores .
Figure 4: The drawing of Nasir al-Din Tusi on a recent Iranian stamp.
Another important characteristic of this work is that its First Treatise contains information about ancient Chinese and Turkish medicine. The book provides information about precious stones and their characteristics. It consists of seven treatises each of which is called a Maqal . While the first six treatises deal with pearl, ruby, emerald, diamond and turquoise, the seventh treatise provides organized information on musk, zebad, anbar, sandal, ud (various perfumes) and camphor, and other eccentric and bizarre stones .
That this book was translated into Turkish in the time of Sultan Murad II, and that it was included in the bibliography of the book Yak’tat al-Mahazin fi Jawahir al-Ma’adin written by Yahya b. Muhammad al-Gaffari in the name of Prince Korkut, suggests that this book was in demand among the Ottomans .
3.6. Tahrir al-Majisti
The Almagest was Ptolemy’s most influential work in the Islamic world. The Tahrir al-Majisti (Exposition of the Almagest)  by Al-Tusi (in Arabic) was also very popular in the Islamic world. The author states he wrote the book due to the encouragement of Husam al-Din al-Hasan b. Muhammad al-Sivasi, whom Al-Tusi calls sayf al-munadhirin (sword of the debaters). There are twenty-two known copies of the work in Turkish libraries.
Nizam al-Din al-Nishaburi wrote a commentary of the work with the title Ta’bir al-Tahrir. Later, Kadizade-i Rumi wrote a work entitled Hashiya ‘ala Kitab al-Majasti (in Arabic) in which he explained certain sections of the commentary of al-Nishaburi .
This treatise Kashf al-qina’ ‘an asrar al-Shakl al-qatta’ (Removal of the Veil from the Mysteries of the Secants Figure) bears sometimes other titles, that is al-Risalat al-qatta’ fi ‘ilm al-Handasa (Treatise on Secants in the Science of Geometry) and Kitab al-shakl al-qatta’ (The Book on the Secant Figure). In all manuscripts, it is in Arabic.
Figure 5: The portrait of the Ottoman Sultan Mehmet II (Muhammad II, 1451-1481).
Al-Tusi’s work is the first systematic trigonometry text, independent of astronomy in Muslim civilization. Hajji Khalifa proposes that this book is related to the first figure in the first chapter of Menelaus of Alexandria’s (c. 70-140 CE) Kitâb al-Ukar’s (Sphaerica). It was also first written in Arabic and then translated into Persian by the author himself as a five-chapter book . The number of copies of the Kashf al-qina’ in the libraries indicates how commonly and frequently it was used through scholars . The French and the Turkish translations of the book in the Ottoman state at the last quarter of 19th century and first quarter of the 20th century shows that this book still very well-liked.
Alexandr Carathéodory published an Arabic edition of the text, accompanied by a French translation . The work was also translated into Turkish by Celal Saygin (d. 1954) . The printing of this book in the Ottoman state at the end of the 19th century and translation of it in the beginning of the 20th century shows how the Ottomans were still interested al-Tusi’s works. “The work in 5 books was written in the State of Assassins for the great magister al-Muayyad ibn Husayn, in 1. On composed ratios (in proposition 1 the notion of “quantity of a ratio” is introduced, for ratio A/B it is quantity Q such that Q/1=A/B, therefore these quantities are equivalent to our real numbers, and the quantity of a ratio composed from two ratios is equal to product of quantities of quantities of these ratios. 2. Theorem of plane figure of secants (plane complete quadrilateral) and proof of the Menelaus theorem for this figure. 3. Introduction to the theory of spherical figure of secants (spherical complete quadrilateral). 4. Proof of the Menelaus theorem for spherical figure of secants. 5. “Methods replacing figure of secants”, that is, spherical theorems of sines and tangents and solution of spherical triangles by three known elements for all six cases, for triangles with three known angles – by means of polar triangle” .
Kitab al-bab al-bahiya fi al-tarakib al-sultaniya or Bahnama-i Padishahi or al-Bah al-Shahiyya , written in Persian, is attributed to al-Tusi . A regimen for the ailing son of the sultan of Qazan, it is divided into three parts of which the first two deal with dietetics and health rules and the third with sexual intercourse. It was translated from Persian into Turkish for the Ottoman Sultan Murad II by a certain Musa b. Mas’ud , about whom nothing is known . Consisting of seventeen chapters, the work takes up subjects such as the temperament of humans, aphrodisiacs, sorbets, pastes and healing drugs .
Works of Nasir al-Din al-Tusi have always attracted the interest of Ottoman scholars from the earliest days until the last period. Some of his works were translated into Turkish and various annotations or commentaries were written upon them. The fact that some of his books were introduced in the madrasas as textbooks shows the importance of his work. A large number of Nasir al-Din al-Tusi’s works, copies of his books and written annotations have lasted until today. It is import to note that most of al-Tusi’s works are being displayed in many libraries of Turkey, especially Istanbul, and in many countries previously governed by the Ottomans in order to understand the broader aspects of his influence. This study examines al-Tusi’s work on scientific fields such as mathematics, astronomy, or mineralogy and demonstrates how important he was to the Ottoman world. In addition, it is important to show how al-Tusi influenced the Ottomans way of thinking by carefully considering his works on religion, faith, philosophy and other social sciences. As a result of this study, Nasir al-Din al-Tusi’s contribution to European philosophy and science via the Ottoman world can also be revealed.
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Ozcan, Abdulkadir. (1991). “Bahnâme”, Diyanet Islam Ansiklopedisi, Istanbul, IV, 489–490.
Ozkaya, Tuten. (1998). “Sovyetler Birligi’nde Nasiruddin-i Tusi’nin Ahlak-i Nasiri Eseri Uzerine Calismalar”, Erdem, 4/10, 273;
Ragep, F. Jamil (2007). “Tusi: Abu Ja’far Mu?ammad ibn Mu?ammad ibn al-?asan Nasir al-Din al-Tusi”, in Biographical Encyclopaedia of Astronomers, ed. Thomas Hockey, New York: Springer, II, 1153-1155.
——— (1984). Comography in the “Tadhkira” of Nasir al-Din al-Tusi, 1-2, Thesis. Ann-Arbor.
——— (2000). “Al-Tusi, Nasir al-Din: As scientist.” In Encyclopaedia of Islam. 2nd ed. Vol. 10, pp. 750–752. Leiden: E. J. Brill.
Rizayev, Agababa. (1996). Nasreddin Tusi: Hayati, Ilmi, Dunya Gorusu, Baku.
Rosenfeld, B. A. and E. Ihsanoglu (2003). Mathematicians, Astronomers, and Other Scholars of Islamic Civilization and Their Works (7th–19th c.). Istanbul: IRCICA, pp. 211–219.
Ruska, J. -R. Strothmann. (1988). “Tusi”, Islâm Ansiklopedisi, Istanbul: MEB, XII, 132-134.
Salih Zeki. (1315). Kâmus-i Riyâziyyât, Istanbul 1315.
——— (1329). Asar-i Bakiye, Istanbul.
Sarton, G. (1931). Introduction to the History of Science, Baltimore.
Sayili Aydin. (1960). The Observatory in Islam. Ankara: Turkish Historical Society.
——— (1972). “Turkish Contributions to and Reform in Higher Education and Huseyin Rifki and His Work in Geometry”, Ankara Universitesi Yilligi, XII. 89-98.
Sesen, Ramazan (1982). Nawâdir al-makhtûtât al-Arabiyya fî maktabati Turkiyâ. Beirut: Dâr al-Kitâb al-Jadid, 1982.
Sesen, Ramazan. (1984). R. Sesen, C. Akpinar, Cevat Izgi. Fihrisu mahtutat al-tibbi al-islami fi maktabati Turkiya. Ed. E. Ihsanoglu. Istanbul: IRCICA.
Sesen, Ramazan. (1991). “On besinci Yuzyilda Turkceye Tercumeler”, Mimar Sinan Fen-Edebiyat Fakultesi Dergisi, I/1, (Aralik), p. 228.
Siddiki, Bahtiyar Huseyin. (1990). Nasuriddin Tusi, trans. Kasim Turhan, Islam Dusuncesi Tarihi (Ed. M. M. Serif), Istanbul.
Spuler, B., (1987). Iran Mogollari Siyaset, Idare ve Kultur Ilhanlilar Devri, 1220-1350 (trs. C. Koprulu), Ankara.
Storey, C. A. (1972). Persian Literature: a Bio-Bibliographical Survey, London.
Sehsuvaroglu, Bedii N. (1967). “Osmanli Padisahlari ve Bahnâmeler”, VI. Turk Tarih Kongresi (Bildiriler), Ankara, pp. 426–428.
Taskopruluzâde. (1328). Miftâhu’s-Sa’âde ve Misbâhu’s-Siyâde, I, Haydarâbâd.
Tekeli, Sevim. (1958). “Nasiruddin, Takiyuddin ve Tycho Brahe’nin Rasat Aletlerinin Mukayesesi”, AU, Dil, Tarih ve Cografya Dergisi, XVI (Ankara), pp. 301-393.
TKITYK. (1984). Turkiye Kutuphaneleri Islâmî Tip Yazmalari Katalogu, Istanbul 1984.
Toderini, M. L’. Abbè. (1789). de la Litterature des Turcs, Traduit de l’Italien en Francois par Tournant, trs. M. L’abbe De Cournand, Paris: Poincot.
 Sarton, G. (1931), 1001–1013; Storey, C. A. (1972), 52–60; Nasr, S. H. (1981), XIII, 508–514; Sayili (1960), 28; Salih Zeki (1329), vol. 1, 178–183; Dilgan Hamit (1968); Izgi Cevat (1997),vol. 1, I, 288; Rosenfeld and Ihsanoglu (2003), 211–219; Ruska (1988), XII, 132–134; Ragep, F. Jamil (2000), pp. 750–752.
 Ozkaya, Tuten (1998), 4/10, 273; Siddiki, Bahtiyar Huseyin (1990), vol. 2, 188; Keklik, Nihat (1983), 2; Bunyatov, Ziya (1991), IV/321; Rizayev, Agababa (1996), 11; Badakhchani, S. J. (1998).
 According to Rosenfeld and Ihsanoglu’s (2003), there are 300 copies of al-Tûsi’s manuscripts in the Turkish libraries.
 Tekeli (1958), 301–393.
 There are nineteen manuscripts named Ta’likât about al-Tûsi’s book in Istanbul Harbiye Military Museum (Askeri Muze, nr. 82).
 Fazlioglu (2011).
 Nasir Al-Din Tusi, Si Fasl dar Ma’rifat-i Taqwîm, Topkapi Palace Museum Library, III Ahmed, nr. 3455, folios 57b-67b. Rosenfeld and Ihsanoglu (2003), 212.
 Akdogan (1999), vol. 1, 169–171.
 Izgi Cevat, (1997), vol. 1, 260–70.
 OALT (1997), vol. 1, 22–24.
 In the opy of manuscript in the Suleymaniye Library (Ayasofya, MS 2709), the commentator added sixty-eight tables and figures to show how to use it.. See OALT (1997), vol. 1, 63–64.
 OALT (1997), vol. 1, 25.
 There are five copies of the translation of Ahmed-i Dai in Bosphorus University, Kandilli Observatory Library: 132/6; 388/2; 371/2; 478; 64/9. See. Kut, Gunay (2007), no. 84–88.
 Ahmed-i Dai also translated al-Tusi’s book Jamasbnâma into Turkish. This book mentions the life of Jamasb son of Prophet Daniel. There is only one copy of this MS: Istanbul University, Literature Faculty, Turk Dili ve Edebiyati, Seminer Library, MS 4028. This translation was published by I. H. Ertaylan as a faximile (Istanbul 1952).
 In the prologue, it says in Turkish: “… Ba’zi mubtedîlere muskil oldugiycun Turkî dile tercume eyleduk”. See: Bayezid Umumi, MS 4604/1. See Izgi Cevat (1997), vol. 2, 421–425; OALT (1997), vol. 1, 3–4; Rosenfeld and Ihsanoglu (2003), 274.
 OALT (1997), vol. 1, 2–5.
 See the other manuscript copies of the translation in these librarires: Istanbul University Library, TY, MS 9807/1, 15 folios; Nuruosmaniye Library, MS 4912; idem, MS 4921 and idem, MS 4971/17.
 For the Turkish Translation in the Latin alphabet see Dizer, M. -T. N. Gencan. (1984).
 Suleymaniye Library, Reisulkuttab, MS 582/3, folios 22b-28a; OALT (1997), vol. 1, 4–5; Izgi Cevat (1997), vol. 1, 260–270.
 Suleymaniye Library, Haci Mahmud, MS 4229/2; Carullah, MS 2108.
 This book was registered at the library of Suleyman Sudi Efendi as Tusi’nin Si Fasl nam Risalesi, but the translator’s name was cited only as Ahmed with the date 1769. See: Ayduz, Salim (2005), 160–170; Ayduz, (2006), 775–812; OALT (1997), vol. 1, 266–7.
 Osman Efendizade Abdullah Efendi, Istihrâc-i Dustûr, Bosphorus University, Kandilli Observatory Library, MS 427, folio 10a.
 Rosenfeld and Ihsanoglu (2003), 212.
 De Young, Gregg (2008-09), 1-72.
 Nasr, Seyyed Hossein (1989), 189.
 Tahrir Usul li-Uqlidis was printed in Matbaa-i Amire in Istanbul in 1216 H (1801) in 222 pages; it was later printed in 1824 in Calcuta, in 1876 in Fez in two volumes and in Iran at an unknown date.
 This book was printed in Roma: Kitab Tahrir Usul li-Uqlidis min ta’lif khwaja Nasir al-Din al-Tusi. Euclidis elementorum geometricorum libri tredecim. Ex traditione doctissimi Nasiridini Tusini. Nunc primum Arabice impressi. Romae: in Typographia Medicea, 1594.
 Toderini, M. L’. Abbè (1789), vol. 1, 100-105.
 Izgi Cevat (1997), vol. 1, 190–200.
 Salih Zeki (1315), vol. 1, 139.
 OMLT (1999), vol. 1, 31-32; OALT (1997), vol. 1, 222-3.
 OMLT (1999), vol. 1, 161-165. Darwish Ahmed Dede b. Lutfullah provides very important information in the prologue of the MS and explains how he managed to write this book. The only copy of the MS is at Bayezid State Library, Umumi, MS 4590/1, folios. 1-29.
 Bursali Mehmed Tahir (1342), vol. 3, 257.
 In the introduction of this MS, Bedruddin Muhammad mentions the names of Sultan Ahmed III., Grand Vizier Ibrahim Pasha and Shaikh al-Islam Ebezade Abdullah Efendi. In the introduction to his work, he claims to have spent some time working on geometry, that he trisected angles, divided circles in seven and arcs in six parts and solved many problems which had not been solved until his time. The figures were given on the sides of the book. The only copy of the book is at Bayezid State Library, Umumi, MS 9787.
 This book was printed four times, the first time in 1797. Bursali Mehmed Tahir (1342), vol. 3, 262; Sayili, Aydin (1972), 89-98.
 Suleymaniye Library, Ayasofya, MS 2620 (see Figure 2).
 Al-Tûsi, Bîst Bâb der Ma’rifet-i Usturlâb, Suleymaniye Library, Veliyyuddin, MS 2269/2, folios 24a-44b; Rosenfeld and Ihsanoglu (2003), 217.
 Suleymaniye Library, Ayasofya, nr. 2641 (see Figure 3).
 OALT (1997), vol. 1,107-8.
 OALT (1997), vol. 2, 788.
 OALT (1997), vol. 1, 351-3.
 Suleymaniye Library, Yahya Tevfik, MS 244/3.
 Suleymaniye Library, Selimiye, MS 1001/2, folios 8b-10b.
 Rosenfeld and Ihsanoglu (2003), 216-7. F. Jamil Ragep had studied this work in his PhD dissertation at Harvard University. see. Ragep (1984).
 Fazlioglu (2003), I/14, 1-66.
 OALT (1997), vol. 1, 44-45.
 Topkapi Palace library, Ahmed III, MS 3314, folio 368.
 Salih Zeki (1315), 392.
 OALT (1997), vol. 1, 21.
 The other most common book on this field is al-Bîrûnî’s al-Jamâhir fî Ma’rifat al-Jawâhir and Muhammad b. Mansûr’s Jawâhirnâma.
 Rosenfeld and Ihsanoglu (2003), 219.
 Taskopruluzade (1328), vol. 1, 272.
 Katip Celebi (1941), 495.
 Sesen, Ramazan (1991), 228.
 Mahmud Shirwani wrote another Jawharnama book named Tuhfa-i Muradi fi asnaf al-jawahir for Sultan Murad II in 1428. There are many copies of this book in the libraries. See: Suleymaniye Library, Bagdatli Vehbi, MS 1465; Suleymaniye Library, Ayasofya, MS 3577. For more information about the manuscript, see OTTBLT (2006), vol. 1, 5-9 and Muhammad b. Mahmud-i Sirvanî (1999).
 The copy of the manuscript at the Suleymaniye Library is in the collection Laleli, MS 2044/4, folios 56b-66b, written in Diwani calligraphy with vowel points. See OTTBLT (2006), vol. 2, 1264-5.
 Suleymaniye Library, Laleli, MS 2044/4, folio 56b.
 Remzi Demir in Mutlu Kilic (2003), 1-64.
 OTTBLT (2006), vol. 1, 18-19.
 F. Sabih Kutlar studied the translation of the book at Beyazid Library, MS 614: see Kutlar, F. Sabih (2001), 17–26. For other copies of the manuscript, see Beyazid State Library, Veliyuddin, MS 2542: Turk Dili Semineri, MS 4464/1; Amasya, MS 614; Talat, Mecami-Turkî, MS 36; Suleymaniye Library, Laleli, MS 2044/4: Muallim Cevdet, MS K 489. For other copies see Rosenfeld and Ihsanoglu (2003), 219.
 Izgi Cevat (1997), vol. 1, 393.
 Rosenfeld and Ihsanoglu (2003), 215.
 OALT (1997), vol. 1, 7-8.
 Salih Zeki (1315), 1493;
 Sesen, Ramazan (1982), III/40. There is only one copy of the book in Suleymaniye Library, Ayasofya, MS 2760, folios 191b-239a.
 Traité du quadrilatère attribué à Nassiruddîn el-Toussy, d’après un manuscrit tiré de la Bibliothèque de S. A. Edhem Pacha (Istanbul 1891). It was reprinted by Fuat Sezgin: Caratheodory, Alexandre Pacha [Transl.]: Traité du Quadrilatère, attribué à Nassiruddin-El-Toussy, Frankfurt am Main: Institute for the History of Arabic-Islamic Science at the Johann Wolfgang Goethe University, 1998 (Islamic Mathematics and Astronomy, vol. 47). OMLT (1999), vol. 2, 412–3; Demir, Remzi (2004), 1–45
 Tarjama-i Kashf al-qina’ ‘an asrar al-Shakl al-qatta’. This is only one copy for this unpublished manuscript: Izmir National Library, Dolap 32, sira 39; Dolap 14, sira 430, Dolap 26, sira 383. OMLT (1999), vol. 2, 512–4.
 Rosenfeld and Ihsanoglu (2003), 214.
 About Bahnama the book and area of research, see Ozcan, Abdulkadir (1991), vol. 4, 489–490.
 According to Ilter Uzel, this book most probably was written by Abu Zayd Mudhaffar. See Mustafa Ebu’l-Feyz, Tuhfetu’l-Muteehhilin-Evlilik Armagani, published and simplified by Ilter Uzel (Ankara: Kebikeç Yayinlari, 2005), 13-15.
 According to Sarton, the name of the book is Kitab al-bab al-bahiya fi al-tarakib al-sultaniya or Bah-nama-i shahi. It was translated by Salah al-Din of Ankara into Turkish. Sarton, Introduction to the History of Science, vol. 2/2, 1010; G. Sarton, Introduction to the History of Science, vol. 3/2, (Baltimore: Carnegie Institution of Washington, 1948), 1077, 1215, 1464.
 Sesen, Ramazan (1984), 378-380. For other copies of the manuscript, see TKITYK (1984), 378.
 For more information about the MS, see Sehsuvaroglu, Bedii N. (1967), 426–428.
 Ayduz, Salim (1999), vol. 1, 611-612.
 Suleymaniye, Hafid Efendi, MS 181/1; OALT (1997), vol. 1, 147.
*Senior Researcher at the Foundation for Science, Technology and Civilisation, UK.