Islamic science in Al-Andalus was still at its peak when the first Christian scholars came to study in Spain. There they learned science from Arabic sources and translated it into Latin, often in collaboration with local multilingual scribes, mostly Jewish, some of whom voluntarily converted to Christianity. At the same time other scholars were at work across Europe, from Toledo to Palermo, translating from Arabic into Latin as well as writing original scientific treatises.
The earliest evidence of European acquisition of Islamic science is a tenth-century Latin manuscript from the library of the monastery of Santa María de Ripoll in Catalonia, now in the archives of the Crown of Aragon in Barcelona. The manuscript begins with a brief treatise on the astrolabe and contains a table of the brightest stars, which are referred to by the Arabic names by which they are still known today, such as Altair, Vega, Rigel, Aldebaran, and Algol. Another tenth-century Latin manuscript, preserved in the Bibliothèque Nationale in Paris, is entitled Mathematica Alhandrei Summi Astrobgi (Mathematics of Alhandreus, Supreme Astrologer). “Alhandreus” appears to be a corruption of “Alkindes,” the Latin for al-Kindi, the ninth-century Islamic philosopher. He writes in the preface, “These are the twenty-eight principal parts or stars [i.e., constellations] through which the fates of all are disposed and pronounced indubitably, future as well as present. Anyone may with diligence forecast goings and returning, origins and endings, by the most agreeable aid of these horoscopes.”
The first major figure in the European acquisition of Greco-Arabic science is Gerbert d'Aurillac (ca. 945-1003), who became Pope Sylvester II (r. 999-1003). Gerbert's writings include a letter he sent in May 984 to a certain Lupitus of Barcelona, whom he asked to send a translation he had made of a treatise on astrology, presumably from an Arabic work.
Gerbert himself is credited with a treatise on the astrolabe entitled De Astrolabia, as well as the first part of a work entitled De Utilitatibus Astro-labi, both of which show Arabic influence. His attested writings also include works on mathematics, one of which is a treatise on the abacus, a calculating instrument that is believed to have come to the Islamic world from China, where it is still in use. He also constructed a device to represent the celestial sphere, which he used in his classes on astronomy in the cathedral school at Rheims. Gerbert's students are known to have gone on to teach at eight other cathedral schools in northern Europe, where his inspiration led them to emphasize the mathematical sciences he had learned from Islamic sources in Spain.
Gerbert later acquired the reputation of being a magician, a legend that seems to have begun in the first half of the twelfth century with William of Malmesbury. William says that Gerbert fled from his monastery to study astrology and the black arts with the Saracens, from whom “he learned what the song and flight of birds portend, to summon ghostlyfiguresfrom the lower world, and whatever humancuriosity has encompassed whether harmful or salutary.” A thirteenth-century manuscript in the Bodleian Library at Oxford says that Gerbert became archbishop and pope with the aid of demons, and that he had a genie in a golden head whom he consulted when solving difficult mathematical problems.
Another key figure in the early transmission of Arabic science to the Latin West is Hermannus the Lame (1013-1054), a son of Count Wolferat of Althausen, in southern Germany. Hermannus is one of the earliest Latin authors to introduce to the Latin West three astronomical instruments that had been widely used in the Islamic world: the astrolabe, the chilinder, and the quadrant. These are described in De Mensure Astrolabi and De Utilitatibus Astrolabi, two works that have been attributed to Hermannus, though the first part of the latter work may be by Gerbert d'Aurillac. All three instruments became widely used in the Latin West for astronomical observations as well as for calculations.
Other works by Hermannus include a primer to teach multiplication and division with the abacus, using only Roman numbers. He also wrote the earliest-known treatise on rithmomachia, a complex board game based on Pythagorean numbers that was very popular in the Latin West during the Middle Ages.
The first of the important translators of Greco-Islamic science from Arabic into Latin is Constantine the African (ca. 1020-1085). An account of his early life is given by a twelfth-century Salerno physician known only as Magister Mattheus F. According to this account, Constantine was a Muslim merchant from Carthage, in North Africa, who visited the Lombard court at Salerno in southern Italy, where he learned that there was no medical literature available in Latin. He went back to North Africa and studied medicine for three years, after which he returned to Salerno, perhaps as early as 1065, with a collection of medical writings in Arabic. A few years later he converted to Christianity and became a monk in the Benedictine abbey at Monte Cassino. There, under the patronage of the famous abbot Desiderius, later Pope Victor III, he spent the rest of his days making Latin translations and compilations from Arabic medical texts.
Petrus Diaconus, the historian of the monastery at Monte Cassino, lists a score of translations by Constantine, including works by Hippocrates and Galen as well as those of the Jewish physician Isaac Israeli and the Arabic writers Ibn al-Jazaar and al-Majusi. His most ambitious work was al-Majusi's Kitab al-Maliki, which he translated as the Pantegne, divided into two ten-chapter sections, “Theorica” and “Practica,” suppressing the name of the author and thus leaving himself open to charges of plagiarism. Constantine appears to have translated only about half of this work, which seems to have been completed by his student Johannes Afflacius.
There is no direct evidence to connect Constantine with the Medical School of Salerno, founded in the mid-eleventh century. Johannes Afflacius seems to have taught there and introduced Constantine's translations into the curriculum under the title of Ars Medicine or Articula, which formed the foundation of a large part of European medical education on into the sixteenth century. Constantine had always emphasized that medicine should be taught as a basic part of natural philosophy, and the “Theorica” section of the Pantegne provided the basis for this integrated study.
The Jewish scholar Isaac Israeli flourished in Tunisia in the first half of the tenth century, where he was court physician to the last Aghlabid emir and then to the Fatimid caliph who succeeded him. His three most important medical works are the Book on Fevers,the Book on Urine, and the Book on Foodstuffs and Drugs, all three of which were translated into Latin by Constantine the African. The first two of these works were popular as textbooks and were also translated into Hebrew. Isaac also wrote a number of short works on philosophy. The best-known of these was the Book of Definitions and Descriptions, largely based on the work of al-Kindi; it was translated into Latin by Gerard of Cremona and became a popular textbook in the first European universities. The book is a collection of fifty-seven definitions, most of them paraphrases and quotes from al-Kindi's terminology, which is used for both terrestrial and celestial objects.
The First Crusade, which began in 1096, led to the establishment of Crusader states in Edessa, Antioch, and Jerusalem, an important factor in opening up Islamic culture to western Europe. One of the earliest examples of this cross-cultural contact is the work of Stephen of Antioch, a translator who flourished in the first half of the twelfth century. According to Matthew of Ferrara, Stephen was a Pisan who went to Syria, probably to the Pisan quarter of Antioch, where his uncle was the Roman Catholic patriarch.
At Antioch Stephen learned Arabic and translated the medical treatise Kitab al-Maliki of al-Majusi into Latin, under the title of Regalis Dispo-sitio; he completed it in 1127. Stephen said that he did so because he felt that the previous translation of this work, by Constantine the African, was incomplete and distorted. He also added a prologue to the second part of the treatise, a list of synonyms in three columns—Arabic, Latin, and Greek—as an aid to help his readers understand the Arabic terms in Dioscorides’ De Materia Medica There he noted that those who have difficulty with the Latin terms can consult experts, “for in Sicily and Salerno, where students of such matters are chiefly to be found, there are both Greeks and men familiar with Arabic.”
Stephen wrote that the Regalis Dispositio was his first work, and he went on to say that he hoped to translate a portion of “all the secrets of philosophy that lie hidden in the Arabic tongue.” This has led to the suggestion that he may be the Stephen Philosophus who wrote several books on astronomy based on Arabic and Greek sources.
Adelard of Bath (ca. 1080-1152) was one of the leading figures in the European acquisition of Arabic science. In the introduction to his Questions Naturales, addressed to his nephew, Adelard writes of his “long period of study abroad,” first in France, where he studied at Tours and taught at Laon. He then went on to Salerno, Sicily, Asia Minor, Syria, and, probably, Palestine and Spain. It was most likely in Spain that Adelard learned Arabic, for his translation of al-Khwarizmi's Sindhind was from the version revised by the Andalusian astronomer Maslama al-Majriti. Adelard's translation, comprising thirty-seven introductory chapters and 116 listings of celestial data, provided Christian Europe with its first knowledge of Greco-Arabic-Indian astronomy and mathematics, including the first tables of the trigonometric sine function to appear in Latin.
Adelard was also the first to translate the full text of Euclid's Elements into Latin, beginning the process that led to Euclid's domination of medieval European mathematics. He did three versions of the Elements, the first being from the Arabic of al-Hajjaj, who had translated it from Greek for Caliph Harun al-Rashid. The second was an abbreviated version that Adelard called a commentum, in which, among other elaborations, he gave “enunciations” (explanations) of the definitions, postulates, axioms, and propositions in Book I of the Elements The third version, which Roger Bacon referred to as an editio specialis, adds more commenta, along with full proofs of all propositions.
Companus of Novara adapted Adelard's second version to produce what is considered to be the best Arabic to Latin translation of the Elements, the earliest extant copy of which is dated 1259. This and the first translation of the Elements from Greek to Latin, by Bartolomeo Zamberti in 1505, formed the basis for most subsequent versions, including those in the vernacular languages of Europe. The first introduction to the Elements in English appears in Robert Recorde's The Pathway to Knowledge, published in London in 1551. Recorde realized that Euclid's axioms would be far beyond the mathematical ability of the “simple ignorant” people who would read his book, “For nother is there anie matter more straunge in the English tunge, than this whereof never booke was written before now, in that tungue.” The first complete English translation, published in London in 1570, was by Sir Henry Billingsley later lord mayor of London, with a “fruitfull Praeface” by John Dee, who writes that the book contains “manifolde additions, Scholies, Annotations and Inventions … gathered out of the most famous and chiefe Mathematicians, both of old time and in our age.”
Adelard says that his Questiones Naturales was written to explain “something new from my Arab studies.” The Questiones are seventy-six in number, 1-6 dealing with plants, 7-14 with birds, 15-16 with mankind in general, 17-32 with psychology, 33-47 with the human body, and 48-76 with meteorology and astronomy. Throughout he looks for natural rather than supernatural causes of phenomena, a practice that would be followed by later European writers. His observations are for the most part accurate, and he remarks that he prefers reason to authority.
One particularly interesting passage in this work comes when Ade-lard's nephew asks him if it were not “better to attribute all the operations of the universe to God.” Adelard replies: “I do not detract from God. Everything that is, is from him and because of him. But [nature] is not confused and without system and so far as human knowledge has progressed it should be given a hearing. Only when it fails utterly should there be a recourse to God.”
The Questiones Naturales remained popular throughout the rest of the Middle Ages, with three editions appearing before 1500, as well as a Hebrew version. Adelard also wrote works ranging from trigonometry to astrology and from Platonic philosophy to falconry. His last work was a treatise on the astrolabe, in which once more he explained “the opinions of the Arabs,” this time concerning astronomy. The treatise describes the workings of the astrolabe and its various applications in celestial measurements, using Arabic terms freely and quoting from his other works, particularly his translations of Euclid's Elements and the planetary tables of al-Khwarizmi.
Toledo became a center for translation from the Arabic after its recapture from the Moors in 1085 by Alfonso VI, king of Castile and León, the first major triumph of the Reconquista, the Christian recon-quest of Al-Andalus. The initiative for the translation movement there seems to have come from Raymond, archbishop of Toledo (1125-51), as evidenced in the dedications of a contemporary Toledan translator, Domenicus Gundissalinus (ca. 1110-ca. 1190).
Gundissalinus, archbishop of Segovia, did several translations and adaptations of Arabic philosophy, including works by al-Kindi, Ibn Rushd, al-Farabi, al-Ghazali, and Ibn Sina, as well as one by the Jewish physician Isaac Israeli. The translations attributed to Gundissalinus were probably done by him in collaboration with others who were fluent in Arabic, though only in one work, the De Anima of Ibn Sina, is his name linked with that of a coauthor. There his collaborator was a converted Jew named John ibn David, the Latin Avendehut, who is usually identified with the translator known as John of Seville.
Gundissalinus also wrote five philosophical works on his own, based largely on the books he had translated as well as on Latin sources. He is credited with introducing Arabic-Judaic Neoplatonism to the Latin West and blending it with the Christian Neoplatonism of Saint Augustine and Boethius. His De Divisione Philosophiae, which incorporates the systems of both Aristotle and al-Farabi as well as others, is a classification of the sciences transcending the traditional division of studies in the trivium(grammar, rhetoric, and logic) and quadrivium (arithmetic, geometry, astronomy, and musical theory), and it influenced later schemes of classification.
Plato of Tivoli is known only through his work, at least part of which he wrote in Barcelona between 1132 and 1146. His name appears only as an editor of translations from the Arabic and Hebrew in collaboration with the Jewish mathematician and astronomer Abraham bar Hiyya ha-Nasi, also known as Abraham Judaeus or, in Latin, Savasorda.
Savasorda's most important work is his Hebrew treatise on practical geometry, which he and Plato of Tivoli translated into Latin in 1145 as the Liber Embadorum This was one of the earliest works on Arabic algebra and trigonometry to be published in Latin Europe, and it contains the first solution of the standard quadratic equation to appear in the West. It was also the earliest to deal with Euclid's On Divisions of Figures, which has survived not at all in Greek and only partially in Arabic. This work influenced Leonardo Fibonacci, who in his Practica Geometriae, written in 1220, devoted an entire section to division of geometrical figures.
Savasorda also collaborated with Plato of Tivoli in translating the Spherica by Theodosius of Bithynia, and the two may also have worked together on books by Ptolemy and al-Battani, as well as on Abu Maslama al-Majriti's treatise on the astrolabe. The translations from the Arabic of seven other works are attributed to Plato, with or without Savasorda, five of them astrological, one on divination, and one medical, now lost. One of these works is Ptolemy's great treatise on astrology, the Tetrabibbs, which Plato of Tivoli translated into Latin as the Tetra-partitium This was the first Latin translation of Ptolemy, appearing before the Almagest and the Geography, evidence of the great popularity of astrology in medieval Europe. It has also been suggested that Plato is the author of the Latin translation from the Arabic of Archimedes’ De Mensura Circuit Plato's translations were used by both Fibonacci and Albertus Magnus, and printed editions of some of them were published in the late fifteenth and early sixteenth centuries.
Plato's translation of al-Majriti's treatise on the astrolabe is dedicated to “John, son of David.” This is probably John of Seville, who in the years 1135–53 translated a score of Arabic works, most of them astrological, but also including an astronomical manual by al-Fargani and a treatise on arithmetic by al-Khwarizmi.
The best known work by John of Seville is his partial translation of the medical section of the pseudo-Aristotelian Secretum Secretorum (The Secret of Secrets). This is an apocryphal work that Aristotle is supposed to have composed for Alexander the Great, which a legendary Muslim sage named Ibn Yahya al-Batrik translated from Greek into Chaldean and then into Arabic. A more complete translation was subsequently made by Philip of Tripoli, who in his preface describes how he was in Antioch when he discovered “this pearl of philosophy… this book which contains something useful about almost every science.”
Translations were also sponsored by Bishop Michael of Tarazona during the years 1119-51, as evidenced by a dedication to him by Hugo Sanctallensis. This appears in Hugo's translation from the Arabic of an abridged version of Ptolemy's Tetrabibbs,entitledCentibquium Hugo's preface says that the Centibquium was commissioned by Michael to serve as a guide to the many astrological works that had been made available to the bishop. Hugo's other translations, all from Arabic sources, are on astrology and various forms of divination, including aeromancy hydro-mancy, and pyromancy, prognostication by observing patterns in air, water, and fire, respectively, as well as two short treatises on spatula-mancy, foretelling the future by examining the shoulder blades of slaughtered animals.
Gerard of Cremona (1114-1187) was by far the most prolific of all the Latin translators. The few details that are known of Gerard's life come mostly from a short biography and eulogy written by his companions in Toledo after his death, together with a list of seventy-one works that he had translated. This document was found inserted at the end of Gerard's last translation, which was of Galen's Tegni with the commentary of ‘Ali ibn Ridwan. It notes that Gerard completed his education in the schools of the Latins before going to Toledo, which he would have reached by 1144 at the latest, when he would have been thirty years old. The vita goes on to say that it was his love of Ptolemy's Almagest, which he knew was not available in Latin, that drew Gerard to Toledo, and “there, seeing the abundance of books in Arabic on every subject… he learned the Arabic language, in order to be able to translate.”
Gerard also lectured on Arabic science, as evidenced by the testimony of the English scholar Daniel of Morley who had first gone to Paris but had left there in disappointment, traveling to Toledo to hear the “wiser philosophers of the world,” as he remarks in hisPhilosophia Daniel gives a detailed account of meeting “Gerard of Toledo” and listening to his public lectures on Abu Ma'shar's Great Introduction to the Science of Astrology He also listened to lectures by Gallipus Mixtarabe, a Mozarab who collaborated with Gerard on his translation of the Almagest, which they seem to have completed in 1175. Otherwise Gerard apparently worked alone, for no collaborators are listed in any of his other translations.
Gerard's translations included Arabic versions of writings by Aristotle, Euclid, Archimedes, Ptolemy, and Galen, as well as works by al-Kindi, al-Khwarizmi, al-Razi, Ibn Sina, Ibn al-Haytham, Thabit ibn Qurra, al-Farghani, al-Farabi, Qusta ibn Luqa, Jabir ibn Hayyan, al-Zarqali, Jabir ibn Aflah, Masha'allah, the Banu Musa, and Abu Ma'shar. The subjects covered in these translations include twenty-four works on medicine; seventeen on geometry, mathematics, optics, weights, and dynamics; fourteen on philosophy and logic; twelve on astronomy and astrology; and seven on alchemy, divination, and geomancy or predicting the future from geographic features.
Gerard may also have published a number of original works, and several have been tentatively attributed to him, including two glosses on medical texts by Isaac Israeli as well as treatises entitled Geomantia Astronomica and Theorica Planetarium However, there is reason to believe that the latter treatise is a work by John of Seville, whose style Gerard adopted in his translations.
More of Arabic science passed to the West through Gerard than from any other source. His translations had a great impact on the development of European science, particularly in medicine, where students in the Latin West took advantage of the more advanced state of medical studies in medieval Islam. His translations in astronomy, physics, and mathematics were also very influential, since they represented a scientific approach to the study of nature rather than the philosophical and theological attitude that had been prevalent in the Latin West.
One of Gerard's contemporaries in Toledo was the Jewish polymath and poet Abraham ibn Ezra (1086-1164), the Latin Avenezra. Ibn Ezra traveled widely, carrying Andalusian Judeo-Muslim culture to Christian Europe, and his visit to London, in 1158-59, helped bring Arabic astrology to England. His Hebrew translation of al-Biruni's Commentary on the Tables of al-Khwarizmi, the Arabic original of which is lost, contains interesting information on the influx of Indian ideas into Arabic mathematics and astronomy in the eighth century. Ibn Ezra's own writings include treatises on mathematics, astrology, chronology, and the astrolabe, as well as a work on biblical commentary that was much admired by Spinoza. His astrological works, which number more than fifty, were very popular in medieval Europe and were translated into French, Catalan, and Latin, and later into other languages.
The twelfth-century scholar known as Hermann of Carinthia seems to have learned Arabic in Spain, possibly in Toledo. He is noted for his translation of the Arabic text of Ptolemy's Planisphaerium, based on the Arabic text of Abu Maslama al-Majriti. Hermann's translation, which is dated 1143, is the only extant source of the Planisphaerium, which treats the problem of mapping circles on the celestial sphere onto a plane, the mathematical basis of the astrolabe. Hermann's other writings include treatises on the astrolabe and astrology, a commentary on Euclid and other mathematical works, and a translation of the astronomical tables of al-Khwarizmi.
Hermann did several of his translations in collaboration with the English scholar Robert of Chester, a younger contemporary of Adelard's; they worked together at several places in southern France and Spain, including Toledo. Robert's solo translations include al-Khwarizmi's Algebra (dated Segovia, 1145); a treatise on the astrolabe (London, 1147); a set of astronomical tables for the longitude of London (1149-50), based upon the tables of al-Zarqali and al-Battani; and a revision, also for the meridian of London, of Adelard's version of the tables of al-Khwarizmi.
Robert also translated De Compositione Alchemie by Romanus Morienus, one of the earliest works on alchemy rendered into Latin, dated 1144. This is an apocryphal work supposedly written by Morienus, a Christian hermit in Jerusalem, to whom the “secrets of all divinity” had been revealed by a mystic named Adfar of Alexandria, who had found and mastered the astrological works of Hermes Trismegistus, the legendary sage.
One of the extant manuscripts of Robert's revisions of al-Khwarizmi's work contains astronomical tables for the longitude of Hereford in England, dated 1178, which have been attributed to the twelfth-century English astronomer Roger of Hereford. Roger wrote several works on astronomy and astrology in the decade 1170-80. One of these, Liber de Divisione Astronomiae, begins with the phrase “In the name of God the pious and merciful,” the traditional opening of an Islamic treatise, suggesting that this is a translation from the Arabic, though the author is unknown.
Alfred of Sareshel, another twelfth-century English scholar, dedicated one of his translations to Roger of Hereford. Alfred did translations of several Aristotelian works from Arabic, together with commentaries, and he also translated the sections on geology and alchemy from Ibn Rushd's Kitab al-Shifa, which he entitled De Mineral-ibus Alfred seems to have learned Arabic in Spain, where he probably did his translation of Ibn Rushd, and he also appears to have used Greek sources, particularly in his works on Aristotle, whose natural philosophy and metaphysics he introduced to England.
The most important interface between the Greek, Latin, and Arabic cultures in the twelfth century was the Norman realm in southern Italy and Sicily, the “Kingdom of the Two Sicilies.” The Normans had driven the Byzantines from their last footholds in southern Italy and then subdued the Saracens in Sicily. When Count Roger I conquered Palermo in 1091, it had been under Muslim domination for nearly two centuries. He reduced the Muslims to the status of serfs except in Palermo, his capital, where he employed the most talented of them as civil servants, so that Greek, Latin, and Arabic were spoken in the Norman court and used in royal charters and registers. Under his son Roger II (r. 1130-54), Palermo became a center of culture for both Christians and Muslims, surpassed only by Cordoba and Toledo. Beginning under Roger II, and continuing with his successors, the Sicilian court sponsored numerous translations from both Greek and Arabic into Latin.
Roger II was particularly interested in geography, but he was dissatisfied with the existing Greek and Arabic geographical works. Thus in 1138 he wrote to al-Idrisi (1100-1166), the distinguished Muslim geographer and cartographer, who was then living in Cueta, and invited him to visit Palermo, saying, “If you live among the Muslims, their kings will contrive to kill you, but if you stay with me you will be safe.” Al-Idrisi accepted the offer and lived in Palermo until Roger's death in 1154, after which he returned to Cueta and passed his remaining days there.
Roger commissioned al-Idrisi to create a large circular relief map of the world in silver, the data for which came from Greek and Arabic sources, principally Ptolemy's Geography, as well as from travelers and the king's envoys. The silver map has long since vanished, but its features were probably reproduced in the sectional maps in al-Idrisi's Arabic geographical compendium, Kitab Nuzhat al-Mushtaqji Ikhtiraq al-Afar, which has survived. The compendium deals with both physical and descriptive geography, with information on political, economic, and social conditions in the lands around the Mediterranean and in the Middle East, and is thus a veritable encyclopedia of the medieval world. Al-Idrisi's work was a popular textbook in Europe for several centuries, and a number of abridgements were done, the first in Rome in 1592. A Latin translation was published in Paris in 1619, and a two-volume French translation was done in 1830-40, entitled Géographic d'Edrisi
Frederick II of Hohenstauffen (r. 1212-50), the Holy Roman emperor and king of the Two Sicilies, was a grandson of the emperor Frederick I Barbarossa and the Norman king Roger II. Known in his time as stupor mundi, “the wonder of the world,” he had been raised from age seven to twelve in Palermo, where he grew up speaking Arabic and Sicilian as well as learning Latin and Greek. When he became emperor in 1211, at the age of fourteen, he turned away from his northern dominions to his Kingdom of the Two Sicilies, where, like his Norman predecessors, who were known as “baptized sultans,” he indulged himself in his harem in the style of an Oriental potentate.
Frederick was deeply interested in science and mathematics, and he invited a number of scholars to his brilliant court, most notably John of Palermo, Master Theodorus, and Michael Scot, calling them his “philosophers.” He subsidized their scientific writings and translations, which included Aristotle's works on physics and logic, some of which he presented in 1232 to the professors at Bologna University. The letter Frederick sent with the gift told of how he had loved learning since his youth, and of how he still took time from affairs of state to read in his library, where numerous manuscripts of all kinds “classified in order, enrich our cupboards.”
Frederick's scholarship is evident in his famous book on falconry, De Arte Venandi cum Avibus (The Art of Hunting with Birds). This is a scientific work on ornithology as well as a detailed and beautifully illustrated manual of falconry as an art rather than a sport. Frederick acknowledged his debt to Aristotle's Zoology, which had been translated by Michael Scot in the thirteenth century. But he was critical of some aspects of the work, as he writes in the preface to his manual: “We have followed Aristotle when it was opportune, but in many cases, especially in that which regards the nature of some birds, he appears to have departed from the truth. That is why we have not always followed the prince of philosophers, because rarely, or never, had he the experience of falconing which we have loved and practiced always.”
One of those with whom Frederick corresponded was the renowned mathematician Leonardo Fibonacci (ca. 1170-after 1240), who had been presented to him when he held court at Pisa in about 1225. Leonardo had at that time just completed his treatise on squared numbers, the Liber Quadratorum, which he dedicated to Frederick, noting, “I have heard from the Podesta of Pisa that it pleases you from time to time to hear subtle reasoning in Geometry and Arithmetic.”
Leonardo, who was born in Pisa, writes about his life in the preface to his most famous work, the book on calculations entitled Liber Abbaci His father, a secretary of the Republic of Pisa, was in around 1192 appointed director of the Pisan trading colony in the Algerian city of Bugia (now Bejaïa). Leonardo was brought to Bugia by his father to be trained in the art of calculating, which he learned to do “with the new Indian numerals,” the so-called Hindu-Arabic numbers, which he would introduce to Europe in hisLiber Abbaci His father also sent him on business trips to Provence, Sicily, Egypt, Syria, and Constantinople, where he met with Latin, Greek, and Arabic mathematicians. In around 1200 he returned to Pisa, where he spent the rest of his days writing the mathematical treatises that made him the greatest mathematician of the Middle Ages.
The five works of Leonardo's that have survived are the Liber Abbaci, first published in 1202 and revised in 1228; the Practica Geometriae (1220-21), on applied geometry; a treatise entitled Flos (1225), sent to Frederick II in response to mathematical questions that had been put to Leonardo by John of Palermo at the time of the emperor's visit to Pisa; an undated letter to Master Theodorus, one of the “philosophers” in the court of Frederick II; and the Liber Quadratorum (1225). This last work contains the famous “rabbit problem”: “How many pairs of rabbits will be produced in a year, beginning with a single pair, if in every month each pair produces a new pair which become productive from the second month on?” The solution to this problem gave rise to the so-called Fibonacci numbers, a progression in which each number is the sum of the two that precede it (e.g., 1, 1, 2, 3, 5, 8, 13, 21…), a mathematical wonder that continues to fascinate mathematicians. Leonardo's sources, where they can be traced, include Greek, Roman, Indian, and Arabic works; by synthesizing them and adding to them with his own creative genius, he stimulated the beginning of the new European mathematics.
Development of the Hindu-Arabic numbers.
Leonardo dedicated his Flos to John of Palermo, whom he also mentions in the introduction to the Liber Quadratorum John's only known work is a Latin translation of an Arabic treatise on the hyperbola, which may be derived from a work by Ibn al-Haytham on the same subject.
Master Theodorus, who is usually referred to as “the Philosopher,” was born in Antioch. He served Frederick as secretary, ambassador, astrologer, and translator, from both Greek and Arabic into Latin, and he was also the emperor's chief confectioner. One of his works is a trans-lation of an Arabic work on falconry. He served the emperor until the time of his death, in around 1250, when Frederick regranted the estate that “the late Theodore our philosopher held so long as he lived.”
Theodorus had probably succeeded Michael Scot as court astrologer. Michael was born in the last years of the twelfth century, probably in Scotland, though he might possibly be Irish. Nothing is known of his university studies, but his references to Paris indicate that he may have studied and lectured there as well as in Bologna, where he did some medical research in 1220 or 1221. He may have learned Arabic and some Hebrew in Toledo, where in about 1217 he translated al-Bitruji's On the Sphere, with the help of Abuteus Levita, a Jew who later converted to Christianity. By 1220 he had completed what became the standard Latin version of Aristotle's On Animals, from a ninth-century Arabic version by al-Bitriq, as well as the De Caelo and the De Anima with Ibn Rushd's commentaries. He had become a priest by 1224, when Pope Honorius II appointed him as archbishop of Cashel, in Ireland, and obtained benefices for him in England. He declined the appointment as archbishop, saying that he did not speak Irish, and was then given further benefices in England and Scotland by the archbishop of Canterbury.
When Leonardo Fibonacci completed his revised version of Liber Abbaci in 1228 he sent it to Michael, who by that time seems to have entered the service of Frederick II as court astrologer. Michael wrote for the emperor a Latin summary of Ibn Rushd's De Animalibus as well as a voluminous treatise known in English as Introduction to Astrology The latter work covers every aspect of astrology and divination, including necromancy or conjuring up the spirits of the dead to reveal the future or influence the course of coming events, as well as nigromancy, or black magic, dealing with dark things performed by night rather than by day.
Michael condemned necromancy and black magic, but he delighted in telling stories of nigromancers and magicians. He says that the best nigromancer in France was a clerk named Gilbertus, presumably Ger-bert d'Aurillac, whom he says conjured up demons who explained to him the use of the astrolabe and the principles of astronomy, after which he reformed and became bishop of Ravenna and then pope.
Frederick addressed a long series of extraordinary questions to Michael, who inserted the questionnaire as an addendum to a work entitled Libers Particularis Frederick's interest in necromancy is indicated in one of the questions he asked Michael: “And how is it that the soul of a living man which has passed away to another life than ours cannot be induced to return by first love or even by hate, just as it had been nothing, nor does it seem to care at all for what it has left behind whether it be saved or lost.” Michael boasted that he could answer all of the questions asked by the emperor, including his query as to “whether one soul in the next world knows another and whether one can return to this life to speak and show one's self; and how many are the pains of hell.”
All of this led to Michael's posthumous fame as a magician, clouding his reputation as a scientist and translator, which is in any event controversial. Roger Bacon referred to Michael as “a notable inquirer into matter, motion, and the course of the constellations,” but at the same time he listed him among those translators who “understood neither sciences nor languages, not even Latin,” and said that his translations were for the most part done by a Jew named Andrew. Bacon credits Michael with having introduced the natural philosophy of Aristotle to the Latin West, though Michael actually transmitted only De Animalibus
Along with Gerbert d'Aurillac, Michael was said to have sold his soul to the devil in exchange for his knowledge of the black arts and the magic of science. Dante writes of him in Canto XX of the Inferno, where he is pointed out in the fourth ditch of the eighth circle of Hell, among the other diviners: “That other, round the loins / So slender of his shape, was Michael Scot / Practised in every slight of magic wile.”
Michael's reputation as a magician of the black arts endured until modern times, particularly in Scotland, where his skill in the black arts was celebrated in a doggerel rhyme:
A wizard, of such dreaded fame,
That when, in Salamanca's cave,
Him listed his magic wand to wave,
The bells would ring in Notre Dame!