The translation programme in Baghdad under the early ‘Abbasids was centred at the famous Bayt al-Hikma, or House of Wisdom, which originally seems to have been basically a library and remained so. Pahlavi manuscripts were kept there and in the early ‘Abbasid period some of these were translated into Arabic. The principal source for the works used and produced by the translators is Abu’l-Faraj Muhammad ibn al-Nadim, whose father was a Baghdad bookseller and who in 987–8 produced a catalogue of the books that were available in the city at that time. Ibn al-Nadim notes that the court astrologer Abu Sahl ibn Nawbakht was employed by Harun al-Rashid at the Bayt al-Hikma, where ‘he translated from Persian into Arabic and relied in his scholarship on the books of Iran...’
Dimitri Gutas writes of the Bayt al-Hikma that ‘It was a library, most likely established as a “bureau” under al-Mansur, part of the ‘Abbasid administration modeled on that of the Sasanians. Its primary function was to house the activity and the results of translations from Persian into Arabic of Sasanian history and culture. As such there were hired translators capable to perform this function as well as book binders for the preservation of books.’ He notes that ‘Under al-Ma’mun it seemed to have gained an additional function related to astronomical and mathematical activities... We have, however, no specific information about what these activities actually were; one would guess research and study only, since none of the people mentioned was himself actually a translator.’
Gutas goes on to say that the Bayt al-Hikma ‘was certainly not a center for the translation of Greek works into Arabic... Among the dozens of reports about the translation of Greek works into Arabic that we have, there is not even a single one that mentions the bayt al-hikma.’ Neither was it ‘an “academy” for teaching the “ancient” sciences as they were being translated,’ he says, nor ‘a “conference” center for the meeting of scholars’. Despite these caveats, from the number of famous translators who were associated with the Bayt al-Hikma it would appear that translations were in fact done there.
It is possible that Aristotle’s Physics was first translated into Arabic during the reign of Harun al-Rashid, the motivation apparently being its use in theological disputations concerning cosmology. Although al-Masudi says that Euclid was translated during the reign of al-Mansur, it would appear that the earliest translation of the Elements was done during Harun al-Rashid’s reign by the mathematician al-Hajjaj ibn Matar (fl. c. 786–833), under the patronage of the vizier Yahya ibn Khalid ibn Barmak.
Harun al-Rashid’s son al-Ma’mun continued the translation programme of his father. Several Muslim and Christian scholars tell the story of how Aristotle appeared to al-Ma’mun in a dream, a legend that was probably concocted, as Dimitri Gutas suggests, to promote ‘caliphal authority at the expense of religious law’. One version of the dream, which became the founding legend of the translation movement, is recounted by Yahya bin ‘Adi:
Al-Ma’mun dreamed that he saw a man of reddish-white complexion with a high forehead, bushy eyebrows, bald head, dark blue eyes and handsome features, sitting on his chair. Al-Ma’mun said: ‘I saw in my dream that I was standing in front of him, filled with awe. I asked, “Who are you?” He replied, “I am Aristotle.” I was delighted to be with him and asked, “O philosopher, may I ask you some questions?” He replied, “Ask.” I said, “What is the good?” He replied, “What is good according to the intellect.” I asked, “Then what?” He replied, “Whatever is good according to religious law.” I asked, “Then what?” He replied, “Whatever is good according to the masses.” I asked, “Then what?” And he replied, “There is no more then.”’
During the reign of al-Ma’mun some mathematicians and astronomers were associated with the Bayt al-Hikma. One of them was al-Hajjaj ibn Matar, who was said by Ibn al-Nadim to have made a second translation of Euclid’s Elements for al-Ma’mun, though other Arabic sources claim differently. Ibn al-Nadim reports that the famous astronomer Muhammad ibn Musa al-Khwarizmi (fl. ca. 828) ‘was employed full-time in the Bayt al-Hikma in the service of al-Ma’mun’.
Al-Khwarizmi is renowned for his treatise Hisab al-jabr wa al-muqabala, known more simply as Algebra, written ca. 825. In his preface he writes that Caliph al-Ma’mun ‘encouraged me to compose a compendious work on algebra, confining it to the fine and important parts of its calculation, such as people constantly require in cases of inheritance, legacies, partition, law-suits and trade, and in all their dealings with one another, or where surveying, the digging of canals, geometrical computation, and other objects of various sorts and kinds are concerned’.
Abu-Kamil Shoja ibn Aslam, an Arabic writer on mathematics, notes that ‘The first thing which is necessary for students in this science [algebra] is to understand the three species which are noted by Muhammad ibn Musa al-Khwarizmi in his book. These are roots, squares and numbers.’ Al-Khwarizmi distinguished six types of problems involving linear and quadratic equations with positive numbers as solutions. After solving these problems numerically in the first five chapters of his book, he tells us in the introduction to the sixth chapter that he will now demonstrate them geometrically: ‘We have said enough so far as numbers are concerned, about the six types of equations. Now, however, it is necessary that we should demonstrate geometrically the truth of the same problems which we have explained in numbers.’
The Turkish historian of science Aydın Sayılı suggests that an Islamic mathematician named ‘Abd-al-Hamid ibn Turk al-Khuttali, working in Baghdad in the first half of the ninth century, may have independently worked along similar lines to al-Khwarizmi in the development of algebra, and he raises the possibility that both of them derived their ideas from an earlier source. According to O’Leary: ‘It may be that mathematics and astronomy came through Indian authorities, not translations from the Greek but based upon Greek teaching, and translations from Greek into Syriac and Arabic came later when efforts were made to check and correct the available material.’ He goes on to say that ‘Certainly the earliest Arab mathematicians, such as al-Khwarizmi, knew a great deal which does not appear in the Greek authors and much of which (but not all) can be traced to Indian workers.’
Following its presence in al-Andalus and elsewhere in Muslim Europe and its use by Muslim scholars, al-Khwarizmi’s Algebra was first translated into Latin by Robert of Chester in 1145, and thus we can see – in a very simplified way – the advancement and spread of disciplines such as algebra through the men who studied such treatises and the cultures that fostered them.
Another of al-Khwarizmi’s mathematical works survives only in a unique copy of a Latin translation entitled De numero indorum (Concerning the Hindu Art of Reckoning). This is the title given to the work in the nineteenth century. The Arabic title was different but no one can be sure of its exact wording and the Arabic version has been lost. This work, which is probably based on Brahmagupta’s Khandakhadyaka, describes the Hindu numerals that eventually became the digits used in the modern western world. The new notation came to be known as that of al-Khwarizmi, corrupted to ‘algorism’ or ‘algorithm’, which now means a procedure for solving a mathematical problem in a finite number of steps that often involves repetition of an operation. De numero indorum explains the use of the Hindu numerals in the four basic operations of addition, subtraction, multiplication and division, dealing with both common and sexagesimal fractions and extracting the square root.
Al-Khwarizmi is the author of the earliest extant original work of Islamic astronomy, the Zij al-Sindhind, based on an Indian work. The Sindhind was most likely used for centuries in the Islamic world and was subsequently updated and revised in al-Andalus by the Arabic astronomer al-Majriti. Al-Majriti’s revision of the Sindhind was translated into Latin early in the twelfth century by Adelard of Bath and was widely used in Europe. Only the Latin translation now survives, the original Arabic work having fallen into disuse in the Islamic world after the twelfth century.
Al-Khwarizmi also wrote the first comprehensive treatise on geography, the Kitab şurat al-ard, or Book of the Form of the Earth. This consists entirely of the latitudes and longitudes of cities and other places, arranged in seven sections according to the climata or ‘climates’ of Ptolemy and other Greek geographers. It has been suggested that al-Khwarizmi’s Form of the Earth is based on an earlier work commissioned by Caliph al-Ma’mun, which was itself derived from Ptolemy’s Geography.
Another extant work of al-Khwarizmi is a short treatise on the Jewish calendar as well as two treatises on the astrolabe and a chronicle of Islamic history.
Important figures in the programme for sponsoring science under al-Ma’mun and his immediate successors were the Banu Musa, three brothers named Muhammed, Ahmad and al-Hasan. These were the sons of Musa ibn Shakir, a former highway robber who became an astrologer in Merv, where he befriended al-Ma’mun before the latter became caliph in 813. When Musa died his three sons were taken into the care of al-Ma’mun, who had them educated in Baghdad after he became caliph. After finishing their studies the Banu Musa served al-Ma’mun and his immediate successors in various ways, becoming rich and powerful in the process. They spent much of their wealth in collecting ancient manuscripts, and they also supported a group of translators in Baghdad.
The Banu Musa themselves are credited with writing some twenty books on mathematics, astronomy and engineering. The most important of their mathematical works is the Book on the Knowledge of Measuring Plane and Spherical Figures, which was translated into Latin in the twelfth century by Gerard of Cremona. Here the Banu Musa used a technique similar to Archimedes’ ‘method of exhaustion’ for determining the area of a circle. Their Premises of the Book of Conics is a recension of the Conics of Apollonius of Perge. They also wrote other works on mechanics and musical theory, the most important of which is The Book of Ingenious Mechanical Devices.
The historian Ibn Khallikan also tells the story, perhaps apocryphal, of how al-Ma’mun directed the Banu Musa to measure the circumference of the earth, to verify the size of the Greek measurement of stadion made by Eratosthenes and other ancient Greek scientists. The method used by the Banu Musa was to measure the north–south distance between two points in the Sinjar desert where the elevation of the pole star differed by one degree, whereupon they multiplied this by 360 to obtain the circumference of the earth. The value they obtained, according to Ibn Khallikan, was 8,000 farsakhs, or 24,000 miles, as compared to the presently accepted value of 24,092 miles.
Two well-known translators in Baghdad were Hunayn ibn Ishaq and Thabit ibn Qurra, both of whom were patronised by the Banu Musa ‘for full-time translation’, according to the philosopher Abu Sulayman al-Sigistani, who says they were paid a salary that put them on a par with the highest officials in the government bureaucracy.
Hunayn ibn Ishaq (808–73), known in Latin as Joannitus, was born at al-Hira in southern Iraq, the son of a Nestorian apothecary. According to Hunayn’s autobiography, he went to Baghdad to study under the Nestorian physician Yuhanna ibn Masawayh (d. 857), personal physician to al-Ma’mun and his successors. But his frequent questions annoyed Ibn Masawayh, who dismissed him and said he was wasting his time studying medicine, when he could be peddling counterfeit coins along the roadway like his compatriots from Hira:
What makes the people of Hira want to study medicine? Go away and find one of your friends; he will lend you fifty dirhems. Buy some little baskets for a dirhem, some arsenic for three dirhems, and with the rest buy coins of Kufa and of Qadisiyya. Coat the money of Qadisiyya with arsenic and put in the baskets and stand by the side of the road crying: ‘Here is true money, good for giving alms and for spending.’ Sell the coins; that will earn you much more than studying medicine.
Hunayn, who at the time knew only Syriac, then went away to ‘the land of the Greeks’ until he became proficient in Greek, after which he lived in Basra for a time to learn Arabic. He then moved to Baghdad, where he soon became a member of the circle of physicians and philosophers who gathered around Caliph al-Wathiq. Al-Wathiq’s successor, Caliph al-Mutawakkil, appointed Hunayn as his head physician, thus ending the monopoly of the Bukhtishu in this post. One of the Bukhtishu managed to turn al-Mutawakkil against him and Hunayn was imprisoned. But when the caliph became ill he released Hunayn and restored him as chief physician, a position he held for the rest of his days. Ibn Khallikan describes Hunayn’s sybaritic life style in his latter years:
He went to the bath every day after his ride and had water poured on him. He would then come out wrapped in a dressing gown and, after taking a cup of wine with a biscuit, lie down until he had stopped perspiring. Sometimes he would fall asleep. Then he would get up, burn perfumes to fumigate his body and have dinner brought in. This consisted of a large fattened pullet stewed in gravy with a half kilo loaf of bread. After drinking some of the gravy and eating the chicken and the bread he would fall asleep. On waking up he drank 4 ratls [perhaps 2 litres] of old wine. If he felt like fresh fruit, he would have some Syrian apples and quinces. This was his habit until the end of his life.
Hunayn and his students, who included his son Ishaq ibn Hunayn and his nephew Hubaish, made translations from Greek into both Syriac and Arabic. Hunayn was indefatigable in his search for Greek manuscripts, as he writes in regard to Galen’s De demonstratione: ‘I sought for it earnestly and traveled in search of it in the lands of Mesopotamia, Syria, Palestine and Egypt until I reached Alexandria, but I was not able to find anything, except about half of it at Damascus.’ He was meticulous and set very high standards for his work, as he remarks in telling of his translation of Galen’s On the Best Sect, known in Latin as De Sectis:
I translated it when I was a young man...from a very defective Greek manuscript. Later when I was forty-six years old, my pupil Hubaish asked me to correct it after having collected a certain number of Greek manuscripts. Thereupon I collated these to produce one correct manuscript and I compared this manuscript with the Syriac text and corrected it. I am in the habit of proceeding thus in all my translation work.
Hunayn writes of the translations of the writings of Galen done by him and his school in a work entitled Hunayn ibn Ishaq’s Missive to ‘Ali ibn Yahya on Galen’s Books Which, so far as He [Hunayn] Knows, Have Been Translated and Some of Those Books Which Have Not Been Translated. Some of these were revisions of earlier translations, such as the one that Hunayn and his colleagues did of Sergius of Reshaina’s translation into Syriac of Galen’s On the Method of Healing. Hunayn, in commenting on this work, remarks that it was one of the books that was studied at the school of medicine in Hellenistic Alexandria: ‘These are the books to which reading was confined at the place of teaching medicine in Alexandria, and were read in the order I have cited them. [Students] gathered every day to read and understand a principal book, in the same way as our Christian companions assemble at present at the places of teaching known as “Schools”.’
Hunayn’s Missive lists 129 of Galen’s works, of which he and his colleagues translated about ninety from Greek into Syriac and the rest into Arabic. The first that he himself did, completed when he was not yet seventeen, was On the Types of Fevers, translating it into Syriac, which he later improved upon when he had better Greek manuscripts. Their translations also included the medical works of Hippocrates, Euclid’s Elements, and De Materia Medica of Dioscorides, which became the basis for Islamic pharmacology. His son Ishaq ibn Hunayn’s extant translation of Aristotle’s Physics is the last and best version of that work in Arabic. His translations included Ptolemy’s Almagest, while his father Hunayn revised the Tetrabiblos. Hunayn himself also revised an earlier translation of Galen by Yahya ibn al-Bitriq (d. 820); these were synopses that contained Plato’s Republic, Timaeus and Laws, the first rendering of the Platonic dialogues into Arabic.
Hunayn was an outstanding physician, though his rivals complained that his medical knowledge came only through his translations. These jealous rivals made his life miserable, Hunayn complains in his treatise On Misfortunes and Hardships Which Befell Him at the Hands of His Adversaries, Those Renowned but Wicked Physicians of His Time, of whom he enumerates fifty-six who at one time or another were in the service of the caliphs.
Hunayn wrote two books on medicine, both extant in Arabic. One of them, Questions on Medicine, a history of the subject, was written in collaboration with his nephew Hubaish; the other a treatise entitled On the Properties of Nutrition, was based on Galen and other Greek writers. Although Hunayn did not make any original contributions to medicine, his medical writings and his translations provided the basis for the education of Arabic-speaking physicians.
Hunayn wrote on a number of other fields as well, the remarkable range of his interests evident in the titles of some of his books: including Book on Meteors, Book on Colors, Treatise on the Comets and Miracles mentioned about Comets, A Greek Grammar, Book on Rainbows, Book of Questions about the Eye, Book on Ebbs and Flows of the Tides, The Truth of Religious Creeds, A Universal History, A Book on the Cause of Seawater Becoming Salty, a Book on Alchemy, and a paraphrase of Aristotle’s On the Heavens.
Thabit ibn Qurra (ca. 836–901) was born in the northern Mesopotamian city of Harran, a centre of the ancient Sabean cult, an astral religion in which the sun, moon and five planets were worshipped as divinities. Several Arabic histories tell the story of how Caliph al-Ma’mun, when he first came to Harran, was shocked to find that the people there were pagans, and he ordered them to adopt one of the recognised religions, Islam, Judaism, Christianity or Mazdeanism. They were alarmed by this and sought the aid of an authority on Islamic law, who ‘advised them to claim to be Sabeans (Sab’ia), as those are mentioned in the Qur’an as one of the “peoples of the Book”’. O’Leary states that ‘The story is obviously apocryphal,’ and he explains ‘how the Harranites came to be called Sabeans, a name which we now recognise as not belonging to them.’
According to Bar Hebraeus, Thabit ‘was originally a money-changer in the market of Harran, and when he turned to philosophy he made wonderful progress and became expert in three languages, Greek, Syriac and Arabic... In Arabic he composed about 150 works on logic, mathematics, astronomy and medicine, and in Syriac he wrote another fifteen books.’
Thabit was ‘discovered’ in Harran by Muhammed ibn Musa, one of the Banu Musa brothers, who was returning from an expedition to find ancient manuscripts in the Byzantine Empire. Muhammed brought the young Thabit back with him to Baghdad, where he became one of the salaried translators who worked for the Banu Musa along with Ishaq ibn Hunayn. After Thabit established himself a number of his fellow Sabeans joined him in Baghdad, where they formed a school of mathematics, astronomy and astrology that lasted through three generations of his family.
Thabit translated writings from both Syriac and Greek into Arabic, including commentaries by Aristotle, Archimedes, Apollonius, Hero, Ptolemy, Nicomachus, Menelaus, Eutocius, Hippocrates and Galen.
Eighty manuscripts of Thabit’s own works survive, including 30 in astronomy, 29 in mathematics, 4 in history, 3 in mechanics, 3 in descriptive geography, 2 in philosophy, 2 in medicine, 2 in mineralogy, 2 in music, 1 in physics and 1 in zoology. Dimitri Gutas lists seventy of his extant works, ten of which cannot be definitely verified as being by Thabit.
Thabit’s original work in mathematics, physics, astronomy and medicine, as well as astrological and talismanic texts, translated from Arabic to Latin, was highly influential in the early development of European science. Roger Bacon refers to him as ‘the supreme philosopher among all Christians, who has added in many respects, speculative as well as practical, to the work of Ptolemy’. But Thabit, as we know, was not a Christian, nor did he ever convert to Islam, for till the end of his days he remained a Sabean, which in Bacon’s eyes would have made him a pagan or heathen, a worshipper of the celestial bodies.
Thabit’s contributions in mathematics include calculating the volume of a paraboloid and giving geometrical solutions to some quadratic and cubic equations. He formulated a remarkable theorem concerning so-called ‘amicable numbers’, where each number of an ‘amicable’ pair is the sum of the proper divisors of the other, the smallest such pair being 220 and 284. His Book on the Composition of Ratios was important in the development of the concept of what a number was. His Treatise on the Secant Figure was used in spherical astronomy. He also gave a generalisation of the Pythagorean theorem that applies to all triangles, whether right or scalene, although he did not prove it. Other treatises deal with solid geometry and problems involving the conic sections and both plane and solid geometry. In two of his books he tries to prove Euclid’s famous fifth postulate, which defines parallel lines, one of the earliest such attempts in the Islamic world to solve a problem that in the nineteenth century gave rise to non-Euclidean geometries.
Thabit’s researches on astronomy include studies of the motion of the sun, moon and stars. In his treatise On the Motion of the Eighth Sphere he revived the erroneous ‘trepidation theory’ of Theon of Alexandria, which held that the pole of the heavens oscillated back and forth, opposed to the correct theory, first given by Hipparchus, that the celestial pole precessed in a circular path. A number of later Arabic astronomers followed Thabit’s version of the theory of trepidation.
Thabit wrote an introduction or ‘study-aid’ to Ptolemaic astronomy and cosmology entitled The Almagest Simplified, (there are apparently three such texts by Thabit) which includes a commentary on Ptolemy’s cosmic scale of distances in the Planetary Hypotheses. Thabit pictured the planets as being embedded in solid spheres with a compressible fluid between the orbs and the eccentric circles, however these concepts originate with Ptolemy. His planetary theory included a mathematical analysis of motion, in which he referred to the speed of a moving body at a particular point in space and time, the so-called instantaneous velocity, a concept that, much later and through many different permutations, became part of modern kinematics.
Thabit has also been credited with writing an astronomical treatise known as The Book of the Solar Year, but recent scholarship has shown that the text is possibly a revision of the one by the Banu Musa. The object of this book was to study the sun’s apparent annual motion among the stars to determine the length of the tropical year, defined to be the time between two successive spring equinoxes. The author criticises Ptolemy’s work in determining the length of the solar year, as he writes in conclusion: ‘As well as the error of calculating the duration of the solar year from a point on the ecliptic, Ptolemy has created further error as a result of his observations themselves: he did not conduct them as they should have been conducted and it is this part of the error that has most seriously damaged the method of computation that he has proposed.’
This measurement is mentioned by Copernicus, who believed that it had been made by Thabit. The value for the sidereal year given in the Book of the Solar Year is 365 days, 6 hours, 9 minutes and 12 seconds, which differs from the currently accepted value by just 2 seconds. The work was apparently part of a project to rewrite the whole of Ptolemy’s Almagest, and it contained a number of innovations which could have been adopted by later Arabic astronomers.
Thabit wrote a commentary on Aristotle’s Physics in which he differed from the Aristotelian theory of natural place and natural motion. According to Aristotle, the four elements occupy concentric spheres, earth at the centre surrounded successively by water, air and fire, and if displaced move up or down to their natural place. Thabit suggested that it is the relative weight of the various elements that causes them to move one way or the other, earth moving downward because it is the heaviest, followed by water, with air and fire going upward because they are lighter.
Thabit also wrote paraphrases on Aristotle’s Analytica Priora and Hermeneutica and Categories and Metaphysics, as well as, possibly, treatises on the Nature of the Stars and Their Influences, Principles of Ethics (though this cannot be confirmed as only a short fragment of such a work exists in Istanbul), Book on Music, Book on Geography (or rather, his translation of Ptolemy’s Geography) as well as a couple of summaries of Ptolemy’s Tetrabiblos, Reasoning on why Seawater Became Salty, Book on Why the Mountains Were Created and a Book on Divisions of the Days of the Week According to Seven Planets (i.e., the sun, moon and five visible planets). Another of Thabit’s original works is entitled The Nature and Influence of the Stars, which laid out the philosophical basis of Islamic astrology. He also wrote several works on the theory and construction of sundials.
Thabit’s single extant work on magic and talismans is entitled Kitab al-hiyal (Book on Ingenious Manners). This survives only in medieval Latin translations bearing the titles De prestigious (On Magic) or De imaginibus (On Images), which has been described as a ‘Handbook for manufacturing metallic, wax and clay images of people, animals, cities or countries for magic operations connected with astrology.’
Thabit’s four extant theological works are all concerned with the Sabeans, their history, chronology, religion and customs. One of them, a Syriac manuscript entitled Book of Confirmation of the Faith of Hanpe, proudly presents Thabit’s claim that the Sabeans were heirs of the ancient pagan culture that civilised the world.
We are the heirs and offspring of paganism which spread gloriously over the world. Happy is he who for the sake of paganism bears his burden without growing weary. Who has civilised the world and built its cities, but the chieftains and kings of paganism? Who made the ports and dug the canals? The glorious pagans founded all these things. It is they who discovered the art of healing souls, and they too made known the art of healing the body and filled the world with civil institutions and with wisdom which is the greatest of goods. Without them the world would be empty and plunged in poverty.
Another prominent figure of the translation movement was Qusta ibn Luqa (ca. 820–ca. 912), who was born near Heliopolis in Syria. He was a Melkite Greek Christian, who knew Syriac and Arabic. Qusta went to work in Baghdad as a physician and translator and also wrote a number of scientific works. He spent his last years as a client of King Sancherib of Armenia, where he died.
According to his Arabic biographers, Qusta was renowned as a physician and was an expert in philosophy, logic, astronomy, geometry, arithmetic and music, his translations including works of Aristarchus, Aristotle, Hero, Diophantus, Galen and Theodosius of Bithynia. His translation of Hero’s Mechanics is the only extant text of that treatise, and his translation of the Arithmetica of Diophantus was vital in the survival of the work, since the last four books of Greek original are lost. His translations of Aristotle’s writings include commentaries by Alexander of Aphrodisias and John Philoponus. He is credited with the translation of books xiv and xv of Euclid’s Elements, and De Materia Medica of Dioscorides, as well as original treatises on medicine, astronomy, metrology and optics. His medical works include a treatise on sexual hygiene, a book on medicine for pilgrims, treatises On Insomnia, On Sleep and Dreams, On Length and Shortness of Life, and On the Diversities of the Character of Men. His treatise On the Difference Between the Spirit and the Soul was translated into Latin by John of Seville, and is referred to by Albertus Magnus and Roger Bacon, among others.
Qusta also wrote a work on magic entitled Epistle concerning Incantations, Adjurations and Amulets, a Latin translation of which is cited by Albertus Magnus. Qusta’s attitude toward sorcery is evident from an anecdote in this book, where he tells the story of ‘a certain great noble of our country’, who believed that a witch had made him impotent. Qusta advised the noble to rub himself down with the gall of a crow mixed with sesame, persuading him that this was an aphrodisiac, and this gave the man such confidence that he overcame his imaginary ailment and regained his sexual powers.
The translation programme at the Bayt al-Hikma would not have been possible without the paper-mills of Baghdad, which were also the source of the profusion of manuscripts produced in the tenth century Islamic renaissance. Books became widely available and the profession of booksellers flourished; by the end of the ninth century there were more than a hundred premises in Baghdad at which books were made. There are known to have been thirty-six libraries in Baghdad when the city was sacked by the Mongols in 1258, and many private libraries as well. Works in philosophy, science, history, literature and all fields of knowledge became available to everyone who was literate. Students and scholars were drawn to Baghdad from all the lands of Islam, along with merchants, artisans and workers in every conceivable field of labour, for by the time of Harun al-Rashid the population had risen to perhaps a million, making it the largest city in the world.
The port city of Basra, founded in 650, also became a thriving metropolis, described by the geographer Yakubi as ‘the world’s greatest city and first centre of commerce and riches’. Its financial centre thronged with Muslim Arabs and Persians as well as Christians, Jews and Indians, with a booming industrial quarter whose sugar factories and spinning mills supplied a large part of the Islamic world, its shipyard building vessels for the port, which handled the major part of trade between Muslim countries and the Orient. Basra also became an important cultural centre, giving birth to a number of notable writers, the most celebrated being the poet Abu Nuwas, who is associated with Harun al-Rashid. As Shehrazade says in the Thousand and One Nights, referring to Abu Nuwas: ‘For you must know that Harun al-Rashid was always wont to send for the poet when he was in an evil humour, in order to distract himself with the improvised poems and rhymed adventures of that remarkable man.’
The scholars who came to Baghdad and Basra brought with them the widest spectrum of beliefs and ideas, the mixed ingredients in the intellectual stew that came to a boil in Baghdad in the time of Harun al-Rashid and his vizier Yahya the Barmakid. The dawn of this enlightenment is commemorated in an encomium by the court poet Ibrahim al-Mosuli:
See you not how the sun grew faint
And when Harun ruled, gave again his light?
O joy that God’s trustee is now Harun,
He of the generous dew, and Yahya his vizier.