Abū ‘l-Fath Mahmūd Ibn Muhammad al-Isfahānī
10th century mathematician from Iran. He flourished around 982 CE in Isfahan, editor of, and commentator on, some books of Apollonius’ Conics. His work on the Conics was known in Europe.
Ibn Wāfid, Abū ‘l-Mutarrif ‘Abd al-Rahmān al-Lakhmī
Physician from Toledo. He lived from 1008 to 1074. He is the author of a treatise on ophthalmology and of another on simple medical substances. The latter was famous in Europe under the title Liber Abenguefith Philosophi de virtutibus medicinarum et ciborum, after its Latin translation by Gherard of Cremone.
Abubacer (and Abentophal, Abentofail)
Abū Bakr Muhammad Ibn Tufayl al-Qaysī
Andalusian philosopher, physician and court official (ca 1100-1185 CE). Born in Andalusia, he died in Morocco where he was appointed as a vizier and physician for Abu Ya’qub Yusuf, the Almohad Caliph, to whom he recommended Ibn Rushd as his own successor when he retired in 1182. Ibn Tufayl is famous for Hay Ibn Yaqzan (Alive son of Awake), a philosophical romance and allegorical tale. The story of Hay Ibn Yaqzan is similar to the later story of Mowgli in Rudyard Kipling’s The Jungle Book in that a baby is abandoned in a deserted tropical island where he is taken care of and fed by a mother wolf.
A Latin translation of the work, entitled Philosophus autodidactus, first appeared in 1671, prepared by Edward Pococke. The first English translation was published in 1708. But Ibn Tufayl’s intellectual legacy was known in Europe since the Middle Ages.
Abū ‘l-Fidā, Ismā’il Ibn Kathīr ‘Imād al-Dīn
Syrian historian and scholar (1273-1331). Among his works: Al-Bidaya wa al-nihaya (The Beginning and the End), Taqwim al-buldan (A Sketch of the Countries), Tarikh Abu-’l-Fida, his chief historical work, also called Mukhtassar tarikh al-bashar (The Concise History of Humanity or An Abridgment of the History at the Human Race), in the form of annals extending from the creation of the world to the 1300s. Abu ‘l- Fida was also well learned in many fields such as botany and materia medica. He wrote a work in many volumes on medicine titled Kunash, and a book on the balance.
His books of history (Tarikh) and geography (Taqwim) were known in the West. The Taqwim Al-Buldan knew many translations into Latin, either partial or complete. One of them is: Abulfedae Tabula Syriae: cum excerpto geographico ex Ibn ol Wardii Geographia et historia naturali / Arabice nunc primum edidit, Latine vertit, notis explanavit Io. Bernhardus Koehler; accessere Io. Iacobi Reiskii … (Lipsiae, 1766).
Albategnius (and Albategni or Albatenius)
Al-Battānī, Abū ‘Abdullāh Muhammad Ibn Jābir Ibn Sinān al-Harrānī as-Sābī
Astronomer and mathematician, born in Harran (now in Turkey) around 853 CE. He died in 929 at Qasr al-Jiss, near Samarra in Iraq. Among his achievements: the determination of the solar year as being 365 days, 5 hours, 46 minutes and 24 seconds; the production of a number of trigonometric relationships; he also used al-Marwazi’s idea of tangents to develop equations for calculating tangents and cotangents, compiling tables of them. His most important work is his Zīj, or set of astronomical tables, known as al-Zīj al-Sābī with 57 chapters, which by way of Latin translation as De Motu Stellarum by Plato of Tivoli in 1116 (printed 1537 by Melanchthon, annotated by Regiomontanus), had great influence on European astronomy. Copernicus mentioned his indebtedness to Al-Battani and quoted him in the De Revolutionibus (1543).
Abū Al-Hasan Alī Ibn Muhammad Ibn Habīb al-Māwardī
Scholar in political science, sociology, jurisprudence, and ethics. He was born in 972 CE in Basra. A jurist of the Shafi’i school, he also made contributions to Qur’anic interpretations, philology and literature. He served as a judge at several Iraqi districts, including Baghdad, and as an ambassador of the Abbasid caliph to several Muslim states. Al-Mawardi’s works on Islamic governance are recognized as classics in the field. His contribution in political science and sociology comprises a number of monumental books, the most famous of which is Al-Ahkam al-Sultaniyya w’al-Wilayat al-Diniyya (The Ordinances of Government), Qanun al-Wazarah (Laws regarding the Ministers), Kitab Nasihat al-Mulk (The Book of Sincere Advice to Rulers), Kitab Aadab al-Dunya w’al-Din (The Ethics of Religion and of this World).
Abū ‘Alī al-Khayyât, Yahyā Ibn Ghālib
Early astronomer-astrologer (c.770-c.835), author of works translated from Arabic into Latin by Plato Tiburnitus into Latin, such as Albohali arabis astrologi antiqvissimi, ac clarissimi de Ivdiciis natiuitatu, Liber Unus (Nurnberg, 1549). This book was edited recently: The Judgments of Nativities by Yahya Ibn Ghalib Khayyat (Tempe, Arizona: the American Federation of Astrologers, 1988).
Abū ‘l-Qāsim Khalaf Ibn al-’Abbās al-Zahrāwī
An Andalusian physician and surgeon (936 – 1013). He is considered as the father of modern surgery, and as Islam’s greatest surgeon, whose comprehensive medical texts, combining Islamic medicine and ancient influences, shaped both Islamic and European surgical procedures up until the Renaissance. His greatest contribution to history is the Kitab al-Tasrif, a thirty-volume encyclopedia of medical practices. It included sections on surgery, medicine, orthopaedics, ophthalmology, pharmacology, nutrition etc.
Al-Tasrif was translated into Latin by Gerard of Cremona in the 12th century. For about five centuries, it was the primary source for European medical knowledge, and served as a reference for doctors and surgeons. Its influence continued in European medicine continued for at least five centuries, extending into the Renaissance.
Abū Ma’shar al-Falakī, Ja’far Ibn Muhammad al-Balkhī
Afghan mathematician, astronomer, astrologer and philosopher (10 August 787 in Balkh, Afghanistan – 9 March 886 in Wasit, Iraq). Many of his works were translated into Latin and were well known amongst many European astrologers, astronomers, and mathematicians during the European Middle Ages.
Abu Ma’shar developed a planetary model which some have interpreted as a heliocentric model. This is due to his orbital revolutions of the planets being given as heliocentric revolutions rather than geocentric revolutions. His work on planetary theory has not survived, but his astronomical data was later recorded by al-Hashimi and al-Biruni.
Some modern historians argued that the writings of Albumasar were very likely the single most important original source of Aristotle’s theories of nature for European scholars, starting a little before the middle of the 12th century.
Albumasar’s astronomical and astrological treatise Kitab al-mudkhal al-kabir ila ‘ilm ahkam an-nujjum was translated into Latin as Introductorium in Astronmiam by John of Seville in 1133, and again by Hermann of Carinthia in 1140.
Alchabitius (Alcabitius, Alcibitius)
Al-Qabīsī, Abū al-Saqr ‘Abd al-’Azīz Ibn Uthmān
10th century astrologer (d. 967), primarily known for his treatise on judicial astrology, Introduction to the Art of Judgments of the Stars, dedicated to the Sultan Sayf al-Dawlah (reigned c. 916-967) of the Hamdanid dynasty, a work which was highly prized in medieval and Renaissance Europe.
13th century Latin translation by John of Seville was printed in 1473 under the title Alchabitii Abdilazi liber introductorius ad magisterium judiciorum astrorum (the work is also known as the Liber isagogicus de planetarum coniunctionibus). Further editions, such as those of 1485 and 1491, often included a commentary by Johannes Dank (“John Danko”) of Saxony, a 14th century author.
Erhard Ratdolt’s edition published in Venice in 1503 (Alchabitius cum commento) also included Dank’s commentary.
Alfarabius, Alpharabius, Pharabius, Abunaser
Al-Fārābī, Abū Nasr Muhammad Ibn Tarkhān
A great scientist and philosopher (ca. 870-950), whose works were translated into Latin very early and had a wide diffusion and influence. Al-Farabi made notable contributions in mathematics, philosophy, epistemology and music.
Al-Farghānī, Abū ‘l-’Abbās Ahmad Ibn Muhammad Ibn Kathīr
One of the famous astronomers in the 9th century. Born in 805 at Ferghana (present Uzbekistan), he worked in Baghdad, where he was connected to the group of scholars led by the brothers Banu Musa. Later he moved to Cairo, where he composed a very important treatise on the astrolabe around 856. There he also supervised the construction of the large Nilometer on the island of al-Rawda (in Old Cairo) in 861. Al-Farghani died around 880.
He was involved in the measurement of the diameter of the Earth together with a team of scientists under the patronage of Caliph al-Ma’mūn in Baghdad. His textbook Elements of astronomy on the celestial motions, written about 833, was translated into Latin in the 12th century and remained very popular in Europe until the time of Regiomontanus. In the 17th century the Dutch orientalist Jacob Golius published the Arabic text on the basis of a manuscript he had acquired in the Near East, with a new Latin translation and extensive notes. The Alfraganus crater on the Moon was named after him.
Al-Ghazālī, Abū Hāmed Muhammad Ibn Muhammad
Born and died in Tus, in Khurasan (eastern province of Iran) between 1058 and 1111 CE, he was a Muslim theologian, jurist, philosopher, and mystic. Al-Imam al-Ghazali remains one of the most celebrated scholars in the history of Islamic thought. His thought had an important influence on both Muslim philosophers and Christian medieval philosophers. Margaret Smith writes in her book Al-Ghazali: The Mystic (London 1944), “There can be no doubt that Al-Ghazali’s works would be among the first to attract the attention of these European scholars”. She adds, “The greatest of these Christian writers who was influenced by Al-Ghazali was St. Thomas Aquinas (1225–1274), who made a study of the Arabic writers and admitted his indebtedness to them. He studied at the University of Naples where the influence of Arab literature and culture was predominant at the time.”
Alghorismus and Algoritmi
Al-Khwārizmī, Abū Ja’far Muhammad Ibn Mūsā
A Muslim mathematician, astronomer, and geographer, who wrote on Hindu-Arabic numerals and was among the first to use zero as a placeholder in positional base notation. The word algorithm derives from his name. His algebra treatise Hisab al-jabr w’al-muqabala gives us the word algebra and can be considered as the first book to be written on algebra. He was born around 780 in Khwārizm (now Khiva, Uzbekistan) and died around 850. He worked most of his life as a scholar in the House of Wisdom in Baghdad.
His Kitab fi ‘l-jabr wa-’l-muqabala (Book on algebra and in opposition) was the first book on the systematic solution of linear and quadratic equations. Consequently he is considered to be the father of algebra. Latin translations of his Arithmetic, on the Indian numerals, introduced the decimal positional number system to the Western world in the 12th century.
Ibn al-Jazzār, Abū Ja’far Ahmed Ibn Ibrāhīm Ibn Abī Khālid al-Qayrawānī
Tunisian physician, born around 878 à Kairouan, where he died in ca. 980. About forty medical works are attributed to him, many of them were translated into Latin: Kitab al-adwiya al-mufrada (Treatise on Simple Drugs) (Liber de Gradibus Simpleium), the Latin translation of which was performed by Constantine the African. His Tibb al-fuqara ‘ wa al-masakin (Medicine for the Poor) represents a literary topic which became especially popular during the Middle Ages, when works of this type were written by different authors, as, for instance, al-Razi and Peter of Spain.
Ibn al-Jazzar’s most important and most influential work is his Zad al- musafir wa-qut al-hadir (Provisions for the Traveller and the Nourishment of the Settled), translated by Constantin the African as Viaticum peregrinorum in 1124. This work, consisting of seven books, is not, as the title suggests, a guide for the traveler, but a systematic medical handbook, discussing the different diseases and their treatment a ”capite ad calcem” (from head to toe) in a concise form.
Al-Hassan Ibn al-Haytham, Abū ‘Alī
Iraqi polymath scientist, who lived in Egypt (965 – 1039-40), called al-Basri, after his birthplace in the city of Basra, he died in Cairo, where he spent a splendid scientific career. He made significant contributions to the principles of optics, as well as to anatomy, astronomy, engineering, mathematics, medicine, ophthalmology, philosophy, physics, psychology, visual perception, and to science in general with his reflections on the scientific method.
Ibn al-Haytham’s most important work is Kitab al-manazir (Book of Optics) which contains the correct model of vision: the passive reception by the eyes of light rays reflected from objects, not an active emanation of light rays from the eyes. It combines experiment with mathematical reasoning. The work contains a complete formulation of the laws of reflection and a detailed investigation of refraction, including experiments involving angles of incidence and deviation. Refraction is correctly explained by light’s moving slower in denser mediums. The work also contains “Alhazen’s problem”—to determine the point of reflection from a plane or curved surface, given the centre of the eye and the observed point—that is stated and solved by means of conic sections.
A Latin translation of Ibn al-Haytham’s greatest work Optics was made by an unknown scholar, probably early in the 13th century. The work had a major influence not only on 13th-century thinkers such as Roger Bacon but also on later scientists such as Kepler (1571–1630).
Al-Kindī, Ya’qūb Ibn Ishāq
Muslim Arab polymath who flourished in Baghdad (c. 801–873 CE). He was a philosopher, scientist, astronomer, chemist, mathematician, musician, physician, and physicist. Al-Kindi was the first of the Muslim Peripatetic philosophers, and among his numerous other accomplishments he is well known for his efforts to introduce Greek philosophy to the Arab world, and as a pioneer in cryptology and physics.
Ametus filius Iosephi
Ahmed Ibn Yūsuf Ibn Ibrāhim al-Misrī Ibn ad-Dāya
Ahmed Ibn Yusuf was born in Baghdad and moved to Damascus in 839, then to Cairo, where he died in 912 CE. He was a mathematician, like his father Yusuf Ibn Ibrahim.
Among his works that brought him fame and influence is his Risala fi ‘l-nisba wa ‘l-tanasub (Treatise on ratio and proportionality). This was translated into Latin by Gherard of Cremona. It influenced early European mathematicians such as Fibonacci. Further, in On similar arcs, he commented on Ptolemy’s Centiloquium. He also wrote a book on the astrolabe, a predecessor of the octant and the sextant. He invented methods to solve tax problems in Liber Abaci. He was also quoted by mathematicians such as Thomas Bradwardine, Jordanus Nemorarius and Luca Pacioli.
His book On similar arcs influenced European mathematicians, as Ahmed Ibn Yusuf proves that similar arcs of circles can be equal and not equal. The proof, like that on ratio and proportion, is based on Euclid. This time it is Propositions 20 and 21 of Book III of Euclid’s Elements which are the main tools used by Ahmed. The complete Arabic text of this treatise was edited by D. Schrader.
Al-Nayrīzī, Abū ‘l-’Abbās al-Fadhl Ibn Hātim
Mathematician from Nayriz, a town near Shiraz. He flourished between ca. 875 and ca. 940. Little is known of his life but we do know that he dedicated some of his works to Caliph al-Mu’tadid (reigned 892-902) so he almost certainly moved to Baghdad and worked there for the caliph. He wrote commentaries on work by Ptolemy and Euclid, compiled astronomical tables, wrote a book for al-Mu’tadid on atmospheric phenomena. Al- Nayrizi’s commentaries on Ptolemy and Euclid were translated into Latin by Gerard of Cremona. He used the so-called umbra (versa), the equivalent to the tangent, as a genuine trigonometric line. He wrote a treatise on the spherical astrolabe, which is very elaborate and seems to be the best Arabic work on the subject.
Al-Nayrizi wrote a book on how to calculate the direction of the sacred holy Ka’bah in Mecca (it was important for Muslims to be able to do this since they had to face that direction five times each day when performing the daily prayer). In this work, he effectively uses the tan function, but he was not the first to use these trigonometric ideas.
Al-Bitrūjī, Nūr al-Dīn Ibn Ishāq
Andalusian astronomer of the 12th century (he died ca. 1204 CE). Born in present-day Morocco, he settled in Seville, and became a disciple of Ibn Tufayl and was a contemporary of Ibn Rushd.
He wrote a Kitab al-hay’a that was translated into Hebrew, and then into Latin (printed in Vienna in 1531). In this book, he advanced a theory on planetary motion in which he wished to avoid both epicycles and eccentrics, and to account for the phenomena peculiar to the wandering stars, by compounding rotations of homocentric spheres. This was a modification of the system of planetary motion proposed by his predecessors, Ibn Bajjah (Avempace) and Ibn Tufayl. But his efforts were unsuccessful in replacing Ptolemy’s planetary model, due to the numerical predictions of the planetary positions in his configuration being less accurate than that of the Ptolemaic model, mainly because he followed Aristotle’s notion of perfect circular motion.
Al-Zarqālī, Abū Ishāq Ibrāhīm Ibn Yahyā al-Naqqāsh
A leading scholar and the foremost astronomer of his time (1028–1087). He flourished in Toledo, where he constructed instruments and conducted theoretical and observational researches in astronomy. Combining theoretical knowledge with technical skill, he excelled at the construction of precision instruments for astronomical use. He constructed a flat astrolabe that was ‘universal,’ for it could be used at any latitude, and he built a water clock capable of determining the hours of the day and night and indicating the days of the lunar months.
Al-Zarqālī also wrote a treatise on the construction of an instrument (an equatorium) for computing the position of the planets using diagrams of the Ptolemaic model. This work was translated into Spanish in the 13th century by order of King Alfonso X in a section of the Libros del Saber de Astronomia.
His work was translated into Latin by Gerard of Cremona in the 12th century, and contributed to the rebirth of a mathematically-based astronomy in Europe. Four centuries later, Copernicus mentioned his indebtedness to Al-Zarqālī and quoted him, in the book that gave new meanings to the term ‘revolution,’ De Revolutionibus Orbium Coelestium.
Ibn Bājja, Abū Bakr Muhammad Ibn Yahyā Ibn al-Sā’ig
Andalusian scientist who was also a philosopher. He let works in astronomy, philosophy, medicine and physics. He was born in Zaragoza in what is today Spain and died in Fez, Morocco, in 1138.
His thoughts had a clear effect on Ibn Rushd and Albertus Magnus. Most of his writings and book were not completed (or well organized) because of his early death.
Ibn Rushd, Abū al-Walīd Muhammad Ibn Ahmad
Andalusian philosopher, physician, and polymath, a master of philosophy, Islamic law, astronomy, medicine, physics, and science. He was born in Cordoba, and died in Marrakech (1126-10 December 1198 CE). His school of philosophy is known as Averroism. He has been described as the founding father of secular thought in Western Europe.
Famous by his commentaries on Aristotle and by his work in medicine, a medical encyclopaedia called Al-Kulliyat fi ‘l-ttib (Generalities in medicine), known in its Latin translation as Colliget. He also made a compilation of the works of Galen (129-200 CE) and wrote a commentary on The Canon of Medicine (Al-Qanun fi ‘t-tibb) of Ibn Sina. In astronomy, Ibn Rushd rejected the eccentric deferents and the Ptolemaic model and instead argued for a strictly concentric model of the universe.
Jacob Anatoli translated several of the works of Ibn Rushd from Arabic into Hebrew in the 1200s. Many of them were later translated from Hebrew into Latin by Jacob Mantino and Abraham de Balmes. Other works were translated directly from Arabic into Latin by Michael Scot. Many of his works in logic and metaphysics have been permanently lost, while others, including some of the longer Aristotelian commentaries, have only survived in Latin or Hebrew translation. The fullest version of his works is in Latin, and forms part of the multi-volume Juntine edition of Aristotle published in Venice (1562-1574).
Ibn Zuhr, Abū Marwān ‘Abd al-Malik Ibn Abī al-’Alā’ Ibn Zuhr
Famous physician of Andalusia and one of the greatest medical clinicians of the western caliphate. Born in Seville in 1091, he studied in Córdoba. After a brief stay in Baghdad and Cairo, he returned to the Islamic West and worked for Almoravides as a physician. Later, Ibn Zuhr worked for ‘Abd al-Mu’min, the first Muwahid ruler, both as physician and a minister. He devoted his career in Seville and died in 1161 C.E.
Ibn Zuhr confined his work only in medicine, field in which he composed several monumental books. Several of his books were translated into Latin and Hebrew and were in great demand in Europe until the 18th century. Only three of his great books have survived: Kitab al-Taysir fi al-Mudawat wa al-Tadbir (The Book of Simplification concerning Therapeutics and Diet), Kitab al-Iqtisad fi Islah Al-Anfus wa al-Ajsad (Book of the Middle Course concerning the Reformation of Souls and the Bodies), and Kitab al-Aghdhiya (Book on Foodstuffs).
Ibn Sīnā, Abū ‘Alī al- Husayn Ibn ‘Abd Allāh
The famous Muslim philosopher and scientist whose leadership is proved by his title, al-Shaykh al-Ra’īs. He was born in 980 in Kharmaithen (near Bukhara, now in Uzbekistan), and died in June 1037 in Hamadan (now in Iran).
He wrote almost 450 works on a wide range of subjects, of which around 240 have survived. In particular, 150 of the surviving works concentrated on philosophy and 40 of them concentrated on medicine. His most famous works are The Book of Healing (Al-Shifa) and The Canon of Medicine, which was a standard medical text at many Islamic and European universities up until the 18th century.
Many of his books were translated into Latin, and published in Italy throughout the 15th and 16th centuries; part of it on the De Anima appeared at Pavia (1490) as the Liber Sextus Naturalium. The Latin editions of part of these works have been modified by the corrections which the European editors applied to them. This concerns Liberatio (An-Najat) as well as Philosophia Orientalis (al-Hikma al-Mashriqiya) and other texts.
Al-Sūfī, Abū al-Husayn ‘Abd al-Rahmān
Well known astronomer (b. December 7, 903 – May 25, 986). He lived at the court of Emir ‘Adhud ad-Dawla in Isfahan, where he conducted his scientific research. He made astronomical observations, which allowed him to contribute several corrections to Ptolemy’s star list and did his own brightness and magnitude estimates which frequently deviated from those in Ptolemy’s Almagest. He identified the Large Magellanic Cloud, which is visible from Yemen, though not from Isfahan; it was not seen by Europeans until Magellan’s voyage in the 16th century.
He designed a full new nomenclature of star names and constellations, relating the ancient heritage to the local knowledge of Arabic and Islamic countries in this field.
The earliest recorded observation of the Andromeda Galaxy was done by him in 964; he described it as a “small cloud”. He observed that the ecliptic plane is inclined with respect to the celestial equator and more accurately calculated the length of the tropical year. He observed and described the stars, their positions, their magnitudes and their color, setting out his results constellation by constellation. For each constellation, he provided two drawings, one from the outside of a celestial globe, and the other from the inside (as seen from the earth). Al Sufi also wrote about the astrolabe, finding numerous additional uses for it. His most famous book, translated into Latin, is Book of Fixed Stars.
Al-Idrīssī, Abū ‘Abdallāh Muhammad al-Charīf al- Idrīssī
Moroccan cartographer, geographer and traveller (ca. 1100-ca. 1165). He was born in Sebta, Northern Morocco under the Almoravids, he died in his city after a long stay in al-Andalus and Sicily, where he lived at the court of King Roger II.
Al Idrissi’s best known work is his map of the world Lawh al-tarsim (Plank of draught), drawn in 1154 while he was in Sicily. He worked on the commentaries and illustrations for 18 years. His map is now known as the ‘Tabula Rogeriana’, his book as the ‘Geografia’. Taken together, they were named Nuzhat al-Mushtak fi Ikhtiraq al-Afaq, dedicated to Roger (whence the nickname of the book, al-Kitab al-Rujari, Roger’s Book). His maps were used extensively during the explorations in the Renaissance. Al-Idrisi became famous in Europe more than other Muslim geographers and several of his books were translated into Latin. It is said that Christopher Columbus used the map which was originally taken from Al-Idrissi’s work.
Jābir Ibn Hayyān, Abū Mūsā
A prominent Muslim polymath (c. 721–c. 815), who excelled in many scientific branches but was immortalized by his contributions in chemistry, that he practiced in its ancient sense, that is by mixing it with alchemist considerations inherited from ancient times. He was also an astronomer and astrologer, engineer, philosopher, pharmacist and physician.
Ibn Hayyan has been widely referred to as the “father of chemistry”. He is widely credited with the introduction of the experimental method in alchemy, and with the invention of numerous important processes still used in modern chemistry today, such as the syntheses of hydrochloric and nitric acids, distillation, and crystallization. His original works are highly esoteric and probably coded. On the surface, his alchemical career revolved around an elaborate chemical numerology based on consonants in the Arabic names of substances and the concept of takwin, the artificial creation of life in the alchemical laboratory.
Many of his books were translated into Latin since the early phase of Arabic-Latin transmission of knowledge. They contributed greatly in launching the European tradition of chemistry and alchemy.
Jābir Ibn Aflah al-Ishbīlī, Abū Muhammad
Andalusian mathematician and astronomer, native of Seville (b. 1100-d. ca. 1150) and a contemporary of Musa Ibn Maymun (Maimonides, 1135-1204). He shares with Jabir Ibn Hayyan the Latin patronym of Geber. His major work, Islah al-majisti (Correction of the Almagest), proved to be a strong influence on scholars throughout the Latin world in the Middle Ages.
Ibn Aflah developed a theorem in spherical trigonometry that bears his name, and created an instrument called in Latin the torquentum for making transformations between spherical coordinates.
Hale or Haly Abbas
‘Alī Ibn ‘Abbās al-Majūsī
A famous Persian physician. Born in Ahwaz, he flourished under the Buwayhid Sultan Adhud al-Dawla. He died in 994. He is considered one of the three greatest physicians of the Eastern Caliphate of his time. Among his important books a medical encyclopaedia called Al-Kitab al-kamil as-sina’a at-tibbiyya (The Complete Book of the Medical Art), known also as Al-Kitab al-Maliki, title under which it was translated into Latin as Liber regalis. Another title given to the work is the Lber pantegni in a version rendered by Constantin the African.
The Maliki is divided into 20 discourses, of which the first half deals with theory and the other with the practice of medicine. Some examples of topics covered are dietetics and materia medica, a rudimentary conception of the capillary system, interesting clinical observations, and proof of the motions of the womb during parturition (e.g. the child does not come out; it is pushed out).
Hali or Haly Heben Rodan, Haly Rodoan
‘Alī Ibn Ridhwān, Abū al Hasan al-Misrī
An Egyptian physician, astrologer and astronomer, born in Jiza (ca. 998-ca. 1061). He was a commentator on Greek medicine, and in particular on Galen and Hippocrates. He is also known for his observation of the Supernova that appeared in the sky in 1006, which he mentioned in his commentary on Ptolemy’s Tetrabiblos.
Among his works: De revolutionibus nativitatum (The Revolutions of Nativities), edited by Luca Gaurico, printed in Venice (1524); Tractatus de cometarum significationibus per xii signa zodiaci (Treatise on the Significations of Comets in the twelve Signs of the Zodiac), printed in Nürnberg (1563).
‘Alī Ibn Abī ‘l-Rijāl, Abū l-Hasan
Andalusian astronomer and mathematician (died after 432 H/1041 CE). He was best known for his book Al-Bari’ fi ahkam l-nujum (The Excellent book on the positions of the stars), which was very influential in medieval astrology and was translated into old Castilian by Jehudah ben Moshe, then into Latin by Aegidius de Tebaldis and Petrus de Regio in 1256: Albohazen Haly filius Abenragel, Praeclarissimus liber completus in judiciis astrorum (printed in Venice 1585 and Basel 1551). The Latin version was subsequently translated into Hebrew, Portuguese, French and English.
Muhammad al-Baghdādī, Abū Mansūr Abd al-Qāhir Ibn Tāhir Ibn Muhammad Ibn ‘Abdallāh al-Tamīmī
He was an Arab mathematician (c. 980–1037) from Baghdad who is best known for his treatise al-Takmila fi’l-Hisab. It contains results in number theory, and comments on works by al-Khwarizmi which are now lost.
To give just one example of his works translated into Latin, we quote his work on the divisions of superficies: De superficierum divisionibus liber Machometo Bagdedino ascriptis nunc primum Ioannis Dee londinensis, et Federici Commandini urbinatis opera in lucem editus. Federici Commandini de eadem re libellus, prinyed in Pesaro in 1570. The influence of this book lasted until the 17th century, when the leading Jesuit mathematician Christoph Clavius, from the famous Collegio Romano, made use of it in his Practical Geometry.
Among his writings, al-Takmila fi’l-Hisab, is a work of major importance in the history of mathematics in which al-Baghdadi considers different systems of arithmetic. These systems derive from counting on the fingers, the sexagesimal system, and the arithmetic of the Indian numerals and fractions. He also considers the arithmetic of irrational numbers and business arithmetic. He further stresses the benefits of each of the systems but seems to favour the Indian numerals.
Omar Tiberiadis (and Omar Alfraganus Tiberiadis, Omar Ben Alfarghani Tiberiadis, Omar Belnalfargdiani Tiberiadis)
‘Umar Al-Tabarī, Abū Hafs Ibn Farkhān
Astronomer and astrologer from Baghdad who flourished around 760-770, known in Latin by his works such as Omar Tiberiadis astronomi preclarissimi Liber de natiuitatibus & interrogationibus (Venitiis, 1503), of which the original title is Kitâb al-Mawâlid (‘Book of Nativities’). Translated by John of Seville in the first half of the 12th century, this book was so influential that it had at least 16 extant manuscripts and five printed editions from 1503 to 1551. In content, it is a standard treatise on the interpretation of nativities, or birth horoscopes, in three books, quoting Ptolemy, Messahallah and Hermes. It begins by ‘Omar Belnalfargdiani Tiberiadis dixit: Scito quod diffinitiones nativitatum in nutritione sunt quatuor…’
Rhazes (and Rhazes, Rasis, Abubater, Bubikir)
Al-Rāzī, Abū Bakr Muhammad Ibn Zakariyā
A physician, philosopher, and scholar, born in Rayy, Iran in 251 H / 865 CE, and died there in 313 / 925. He made fundamental and enduring contributions to the fields of medicine, alchemy, and philosophy, recorded in over 184 books and articles in various fields of science.
Yuhanna Ibn Sarâbiyûn
A physician and geographer of the 3rd century H /9th century CE. His medical work was well known in the European Latin world after the translation of some of his books, such as Ioannis Serapionis De simplicium medicamentorum historia libri septem (Venetiis: apud Andream Arriuabenium, 1552), and Serapionis medici arabis celeberrimi Practica studiosis medicinae utilissima quam postremo Andreas Alpagus Bellunensis in Latinum convertit, cujus translatio nunc primum exit in lucem (Venetiis : Apud Iuntas, 1550).
He wrote a Small and a Great Compendium, both in Syrian. The Syrian originals are unfortunately lost, but we still have fragments of different Arabic translations, as well as complete Latin and Hebrew versions of the Small Compendium. This book is a medical encyclopedia in seven books.
As a geographer, Ibn Sarabiyun authored a book on geography: Kitab ‘aja’ib al-aqalim al-sab’a ila nihayat al-’imara, containing a description of the various seas, islands, lakes, mountains and rivers of the world. His descriptions of the Euphrates, Tigris and the Nile are very significant. His account of the canals of Baghdad is our main basis of the reconstruction of the medieval plan of that city.
al-Juzjānī, Abū ‘Ubayd Abd al-Wāhid Ibn Muhammad
A Persian physician from Juzjan in Afghanistan (980-1037). He was the closest disciple of Ibn Sīnā. He spent many years with his master in Isfahan, becoming his lifetime companion. Our knowledge of Ibn Sina’s life is due in part to the biography composed by al-Juzjani. It is published in English under the title Avicenna, his Life and Work (London, 1958). Gilbert Sinoué took it as a basis for his book Avicenne ou la route d’Ispahan (Paris, 1989).
This biography was translated into Latin by Niccolò Massa as Vita (ipsius) Avicennae ex Sorsano Arabe ejus discipulo in the 16th century.
Thābit Ibn Qurra Ibn Marwan al-Sābī al-Harrānī
Well known astronomer and mathematician. Thabit was born in Harran (Mesopotamia, in modern day Turkey) in 836 CE. At the invitation of Muhammad bin Musa bin Shakir, one of the Banu Musa brothers, he accompanied him to Baghdad when he carried a brilliant scientific career, besides being a physician and scholar. Of Sabian religion, he never embraced Islam, but this did not hinder his career or the integration of the Sabian community in the highest circles of the Abbasid scientific and intellectual elite. Thabit died in Baghdad in February 18, 901 CE.
Thabit and his pupils lived in the midst of a most intellectually vibrant milieu in Baghdad. He occupied himself with mathematics, astronomy, astrology, mechanics, medicine, and philosophy. His native language was Syrian, which was the eastern Aramaic dialect from Edessa, and he knew Greek well too. He dealt with the Arabic translations from Greek of the works of Apollonius, Archimedes, Euclid and Ptolemy. He had the mission to revise and edit several of these translations, besides authoring his own scientific works.
The medieval astronomical theory of the trepidation of the equinoxes is often attributed to Thabit. According to Copernicus, Thabit determined the length of the sidereal year as 365 days, 6 hours, 9 minutes and 12 seconds (an error of 2 seconds). Copernicus based his claim on the Latin text attributed to Thabit. In mathematics, Thabit discovered an equation for determining the amicable numbers. He also wrote on the theory of numbers, and extended their use to describe the ratios between geometrical quantities, a step that the Greeks never took. Another important contribution Thabit made to geometry was his generalization of the Pythagorean theorem, which he extended from special right triangles to all triangles in general, along with a general proof.
In physics, Thabit rejected the Peripatetic and Aristotelian notions of a “natural place” for each element. He instead proposed a theory of motion in which both the upward and downward motions are caused by weight, and that the order of the universe is a result of two competing attractions (jadhb): one of these being “between the sublunary and celestial elements”, and the other being “between all parts of each element separately”. In mechanics, he is the author of Kitab fi ‘l-qarastun, the book that established the theory of the steelyard balance as a mental model for the Arabic science of weights. Gherard of Cremona translated this groundbreaking treatise into Latin under the title Liber karastonis.
Banū Mūsā Ibn Shākir al-Munajjim (Muhammad, Ahmad, and al-Hassan)
The Banū Mūsā brothers (“Sons of Mūsā Ibn Shakir”) were three scholars at Baghdad, active in the House of Wisdom: Ja’far Muhammad Ibn Mūsā (800-873), who specialized in astronomy, engineering, geometry and physics, Ahmad Ibn Mūsā Ibn Shākir (805-873), who specialized in engineering and mechanics, Al-Hasan Ibn Mūsā (810–873), who specialized in engineering and geometry.
The Banū Mūsā brothers were among the first group of mathematicians who faced the hard task to carry forward the mathematical developments in Islamic civilization in the first half of the 9th century. Their most famous treatise is Kitāb ma’rifat masāhat al-ashkāl al-basīta wa ‘l-kuriya (The Book of the Measurement of Plane and Spherical Figures) in which they made important mathematical contributions. This work became well known through the translation into Latin by Gherard of Cremona under the title Liber trium fratum de geometria.
The three brothers are most known by their achievements in mechanics. Their book Kitāb al-hiyal (The Book of Ingenious Devices) is an outstanding contribution in the field of mechanical sciences. Although it is ascribed to them jointly, certain testimonies ascribe it to Ahmad Ibn Mūsā, who seems to be the mechanic of the group.
Abū Abdullah Muhammad Ibn Yūsuf Ibn Ahmad Ibn Mu’ādh al-Jayyānī
Brilliant Andalusian mathematician (b. 989, Cordova, Al-Andalus – d. 1079, Jaen, Al-Andalus). He wrote important commentaries on Euclid’s Elements and he wrote the first treatise on spherical trigonometry. Little is known about his life. Some of his works translated into Latin were ascribed to Alhazen, the Latinised name of Ibn al-Haytham, such as the famous Liber de crepusculis (Treatise on twilight), in which height of the atmospheric moisture responsible for the refraction of the sun’s rays is calculated. This work, generally ascribed to Alhazen, is the work of al-Jayyani.
Among his known works, Tabulae Jahen cum regulis suis is a set of astronomical tables for Jaen, an Andalusian city.
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