Mathematics in medieval Islam
Mathematics during the Golden Age of Islam during the 9th and 10th centuries, was built on Greek mathematics and Indian mathematics. Important progress was made, such as the full development of the decimal place-value system to include decimal fractions, the first systematised study of algebra, advances in geometry and trigonometry. Arabic works played an important role in the transmission of mathematics to Europe during the 10th to 12th centuries; the study of algebra, the name of, derived from the Arabic word meaning completion or "reunion of broken parts", flourished during the Islamic golden age. Muhammad ibn Musa al-Khwarizmi, a scholar in the House of Wisdom in Baghdad, is along with the Greek mathematician Diophantus, known as the father of algebra. In his book The Compendious Book on Calculation by Completion and Balancing, Al-Khwarizmi deals with ways to solve for the positive roots of first and second degree polynomial equations, he introduces the method of reduction, unlike Diophantus, gives general solutions for the equations he deals with.
Al-Khwarizmi's algebra was rhetorical, which means that the equations were written out in full sentences. This was unlike the algebraic work of Diophantus, syncopated, meaning that some symbolism is used; the transition to symbolic algebra, where only symbols are used, can be seen in the work of Ibn al-Banna' al-Marrakushi and Abū al-Ḥasan ibn ʿAlī al-Qalaṣādī. On the work done by Al-Khwarizmi, J. J. O'Connor and Edmund F. Robertson said: "Perhaps one of the most significant advances made by Arabic mathematics began at this time with the work of al-Khwarizmi, namely the beginnings of algebra, it is important to understand just. It was a revolutionary move away from the Greek concept of mathematics, geometry. Algebra was a unifying theory which allowed rational numbers, irrational numbers, geometrical magnitudes, etc. to all be treated as "algebraic objects". It gave mathematics a whole new development path so much broader in concept to that which had existed before, provided a vehicle for the future development of the subject.
Another important aspect of the introduction of algebraic ideas was that it allowed mathematics to be applied to itself in a way which had not happened before." Several other mathematicians during this time period expanded on the algebra of Al-Khwarizmi. Abu Kamil Shuja' wrote a book of algebra accompanied with geometrical proofs, he enumerated all the possible solutions to some of his problems. Abu al-Jud, Omar Khayyam, along with Sharaf al-Dīn al-Tūsī, found several solutions of the cubic equation. Omar Khayyam found the general geometric solution of a cubic equation. Omar Khayyam wrote the Treatise on Demonstration of Problems of Algebra containing the systematic solution of cubic or third-order equations, going beyond the Algebra of al-Khwārizmī. Khayyám obtained the solutions of these equations by finding the intersection points of two conic sections; this method had been used by the Greeks, but they did not generalize the method to cover all equations with positive roots. Sharaf al-Dīn al-Ṭūsī developed a novel approach to the investigation of cubic equations—an approach which entailed finding the point at which a cubic polynomial obtains its maximum value.
For example, to solve the equation x 3 + a = b x, with a and b positive, he would note that the maximum point of the curve y = b x − x 3 occurs at x = b 3, that the equation would have no solutions, one solution or two solutions, depending on whether the height of the curve at that point was less than, equal to, or greater than a. His surviving works give no indication of how he discovered his formulae for the maxima of these curves. Various conjectures have been proposed to account for his discovery of them; the earliest implicit traces of mathematical induction can be found in Euclid's proof that the number of primes is infinite. The first explicit formulation of the principle of induction was given by Pascal in his Traité du triangle arithmétique. In between, implicit proof by induction for arithmetic sequences was introduced by al-Karaji and continued by al-Samaw'al, who used it for special cases of the binomial theorem and properties of Pascal's triangle; the Greeks had discovered irrational numbers, but were not happy with them and only able to cope by drawing a distinction between magnitude and number.
In the Greek view, magnitudes varied continuously and could be used for entities such as line segments, whereas numbers were discrete. Hence, irrationals could only be handled geometrically. Islamic mathematicians including Abū Kāmil Shujāʿ ibn Aslam and Ibn Tahir al-Baghdadi removed the distinction between magnitude and number, allowing irrational quantities to appear as coefficients in equations and to be solutions of algebraic equations, they worked with irrationals as mathematical objects, but they did not examine their nature. In the twelfth century, Latin translations of Al-Khwarizmi's Arithmetic on the Indian numerals introduced the decimal positional number system to the Western world, his Compendious Book on Calculation by Completion and Balancing presented the first systematic s
Brethren of Purity
The Brethren of Purity were a secret society of Muslim philosophers in Basra, Iraq, in the 8th or 10th century CE. The structure of this mysterious organization and the identities of its members have never been clear, their esoteric teachings and philosophy are expounded in an epistolary style in the Encyclopedia of the Brethren of Purity, a giant compendium of 52 epistles that would influence encyclopedias. A good deal of Muslim and Western scholarship has been spent on just pinning down the identities of the Brethren and the century in which they were active; the Arabic phrase Ikhwān aṣ-Ṣafāʾ can be translated as either the "Brethren of Purity" or the "Brethren of Sincerity". A suggestion made by Ignác Goldziher, written about by Philip Khuri Hitti in his History of the Arabs, is that the name is taken from a story in Kalilah waDimnah, in which a group of animals, by acting as faithful friends, escape the snares of the hunter; the story concerns a Barbary dove and its companions who get entangled in the net of a hunter seeking birds.
Together, they leave themselves and the ensnaring net to a nearby rat, gracious enough to gnaw the birds free of the net. Soon a tortoise and gazelle join the company of animals. After some time, the gazelle is trapped by another net. In the final turn of events, the gazelle repays the tortoise by serving as a decoy and distracting the hunter while the rat and the others free the tortoise. After this, the animals are designated as the "Ikwhan al-Safa"; this story is mentioned as an exemplum when the Brethren speak of mutual aid in one risala, a crucial part of their system of ethics, summarized thus: In this Brotherhood, self is forgotten. The Brethren met on a fixed schedule; the meetings took place on three evenings of each month: once near the beginning, in which speeches were given, another towards the middle concerning astronomy and astrology, the third between the end of the month and the 25th of that month. During their meetings and also during the three feasts they held, on the dates of the sun's entry into the Zodiac signs "Ram and Balance", beyond the usual lectures and discussions, they would engage in some manner of liturgy reminiscent of the Harranians.
Hierarchy was a major theme in their Encyclopedia, unsurprisingly, the Brethren loosely divided themselves up into four ranks by age. Compare the similar division of the Encyclopedia into four sections and the Jabirite symbolism of 4; the ranks were: The "Craftsmen" – a craftsman had to be at least 15 years of age. The "Political Leaders" – a political leader had to be at least 30 years of age. There have been a number of theories as to the authors of the Brethren. Though some members of the Ikhwan are known, it is not easy to work out who, or how many, were part of this group of writers; the members referred to themselves as "sleepers in the cave". In one passage they give as their reason for hiding their secrets from the people, not as fear of earthly violence, but as desire to protect their God-given gifts from the world, yet they were well aware that their esoteric teachings might provoke unrest, the various calamities suffered by the successors of the Prophet may have seemed good reason to remain hidden.
Among the Isma'ili groups and missionaries who favored the Encyclopedia, authorship was sometimes ascribed to one or another "Hidden Imam". Some modern scholars have argued for an Ismaili origin to the writings. Ian Richard Netton writes in "Muslim Neoplatonists" that: "The Ikhwan's concepts of exegesis of both Quran and Islamic tradition were tinged with the esoterism of the Ismailis." Whilst according to Yves Marquet, "It seems indisputable that the Epistles represent the state of Ismaili doctrine at the time of t
Maslama al-Majriti or Abu al-Qasim al-Qurtubi al-Majriti was an Arab Muslim astronomer, mathematician and Scholar in Islamic Spain, active during the reign of Al-Hakam II. Al-Majriti took part in the translation of Ptolemy's Planispherium, improved existing translations of the Almagest and improved the astronomical tables of al-Khwarizmi, aided historians by working out tables to convert Persian dates to Hijri years, introduced the techniques of surveying and triangulation. According to Şā ` id ibn Ahmad Andalusī he was astronomer of his time, he introduced new surveying methods by working with his colleague Ibn al-Saffar. He wrote a book on taxation and the economy of Al-Andalus, he edited and made changes to the parts of the Encyclopedia of the Brethren of Sincerity when the encyclopaedia arrived in Al-AndalusAl-Majriti predicted a futuristic process of scientific interchange and the advent of networks for scientific communication. He built a school of Astronomy and Mathematics and marked the beginning of organized scientific research in Al-Andalus.
Among his students were Ibn al-Saffar, Abu al-Salt and Al-Tartushi. From his date of death, inconsistencies result in the dating of two influential works in early chemistry attributed to him, as either they were published long after his death, or they were the work of someone else claiming some of his glory: the latter is the current general belief; the two works are the "Sage's Step/The Rank of the Wise" and the "Aim of the Wise". Both were translated into Latin, in a version somewhat bowdlerised by Christian dogma, in 1252 on the orders of King Alfonso X of Castile; the Rutbat includes alchemical formulae and instructions for purification of precious metals, was the first to note the principle of conservation of mass, which he did in the course of his pathbreaking experiment on mercuric oxide: I took natural quivering mercury, free from impurity, placed it in a glass vessel shaped like an egg. This I put inside another vessel like a cooking pot, set the whole apparatus over an gentle fire.
The outer pot was in such a degree of heat that I could bear my hand upon it. I heated the apparatus night for forty days, after which I opened it. I found that the mercury had been converted into red powder, soft to touch, the weight remaining as it was originally; the Ghayat is more concerned with advanced esotericism, principally astrology and talismanic magic, although he goes into prophecy. The author considers this the advanced level of work referring to the Rutbat as the foundation text. Several modern sources state that al-Majriti had a daughter, Fatima of Madrid, an astronomer. However, the earliest known mention of her is a short biographical article on her in the Enciclopedia universal ilustrada europeo-americana, published in the 1920s. Al-Andalus Alchemy Arcanum corallinum Vernet, Juan. "Al-Majrītī Abu'L-Qāsim Maslama Ibn Aḥmad Al-Faraḍī". Complete Dictionary of Scientific Biography. Encyclopedia.com. Casulleras, Josep. "Majrīṭī: Abū al‐Qāsim Maslama ibn Aḥmad al‐Ḥāsib al‐Faraḍī al‐Majrīṭī".
In Thomas Hockey. The Biographical Encyclopedia of Astronomers. New York: Springer. Pp. 727–8. ISBN 978-0-387-31022-0
Hunayn ibn Ishaq
Hunayn ibn Ishaq al-Ibadi was an influential Arab Nestorian Christian translator, scholar and scientist. He and his students transmitted their Arabic and Syriac translations of many classical Greek texts throughout the Islamic world, during the apex of the Islamic Abbasid Caliphate. Ḥunayn ibn Isḥaq was the most productive translator of Greek medical and scientific treatises in his day. He studied Greek and became known among the Arabs as the "Sheikh of the translators", he is the father of Arab translations. He mastered four languages: Arabic, Syriac and Persian, his translations did not require corrections. He was from al-Hira, the capital of a pre-Islamic cultured Arab kingdom, but he spent his working life in Baghdad, the center of the great ninth-century Greek-into-Arabic/Syriac translation movement, his fame went far beyond his own community. In the Abbasid era, a new interest in extending the study of Greek science had arisen. At that time, there was a vast amount of untranslated ancient Greek literature pertaining to philosophy, natural science, medicine.
This valuable information was only accessible to a small minority of Middle Eastern scholars who knew the Greek language. In time, Hunayn ibn Ishaq became arguably the chief translator of the era, laid the foundations of Islamic medicine. In his lifetime, ibn Ishaq translated 116 works, including Plato’s Timaeus, Aristotle’s Metaphysics, the Old Testament, into Syriac and Arabic. Ibn Ishaq produced 36 of his own books, 21 of which covered the field of medicine, his son Ishaq, his nephew Hubaysh, worked together with him at times to help translate. Hunayn ibn Ishaq is known for his translations, his method of translation, his contributions to medicine, he has been suggested by François Viré to be the true identity of the Arabic falconer Moamyn, author of De Scientia Venandi per Aves. Hunayn ibn Ishaq was a Nestorian Christian, born in 809, during the Abbasid period, in al-Hirah, to an ethnic Arab family. Hunayn in classical sources is said to have belonged to the ʿIbad, thus his nisba "al-Ibadi.
The ʿIbad was an Arab community composed of different Arab tribes that had once converted to Nestorian Christianity and lived in al-Hira. They were known for their high-literacy and multilingualism being fluent in Syriac, their liturgical and cultural language, besides their native-Arabic; as a child, he learned the Arabic languages. Although al-Hira was known for commerce and banking, his father was a pharmacist, Hunayn went to Baghdad in order to study medicine. In Baghdad, Hunayn had the privilege to study under renowned physician Yuhanna ibn Masawayh. Hunayn promised himself to return to Baghdad, he went abroad to master the Latin language. On his return to Baghdad, Hunayn displayed his newly acquired skills by reciting the works of Homer and Galen. In awe, ibn Masawayh reconciled with Hunayn, the two started to work cooperatively. Hunayn was motivated in his work to master Greek studies, which enabled him to translate Greek texts into Syriac and Arabic; the Abbasid Caliph al-Mamun noticed Hunayn's talents and placed him in charge of the House of Wisdom, the Bayt al Hikmah.
The House of Wisdom was an institution where Greek works were translated and made available to scholars. The caliph gave Hunayn the opportunity to travel to Byzantium in search of additional manuscripts, such as those of Aristotle and other prominent authors. In Hunayn ibn Ishaq’s lifetime, he devoted himself to working on a multitude of writings. Hunayn wrote on a variety of subjects that included philosophy and medicine. In “How to Grasp Religion,” Hunayn explains the truths of religion that include miracles not made by humans and humans’ incapacity to explain facts about some phenomena, false notions of religion that include depression and an inclination for glory, he worked on Arabic lexicography. Hunayn ibn Ishaq enriched the field of ophthalmology, his developments in the study of the human eye can be traced through his innovative book, “Ten Treatises on Ophthalmology.” This textbook is the first known systematic treatment of this field and was most used in medical schools at the time. Throughout the book, Hunayn explains its anatomy in minute detail.
Hunain emphasized that he believed the crystalline lens to be in the center of the eye. Hunain may have been the originator of this idea; the idea of the central crystalline lens was believed from Hunain's period through the late 1500s. He discusses the nature of cysts and tumors, the swelling they cause, he discusses how to treat various corneal ulcers through surgery, the therapy involved in repairing cataracts. “Ten Treatises on Ophthalmology” demonstrates the skills Hunayn ibn Ishaq had not just as a translator and a physician, but as a surgeon. Hunayn ibn Ishaq's reputation as a scholar and translator, his close relationship with Caliph al-Mutawakkil, led the caliph to name Hunayn as his personal physician, ending the exclusive use of physicians from the Bukhtishu family. Despite their relationship, the caliph became distrustful.
Abū ʿAbd Allāh Muḥammad ibn Jābir ibn Sinān al-Raqqī al-Ḥarrānī aṣ-Ṣābiʾ al-Battānī was an Arab astronomer and mathematician. He introduced a number of trigonometric relations, his Kitāb az-Zīj was quoted by many medieval astronomers, including Copernicus. Al-Battani is sometimes referred to as the "Ptolemy of the Arabs", is considered the greatest and best known astronomer of the medieval Islamic world. Little is known about al-Battānī's life beside that he was born in Harran near Urfa, in Upper Mesopotamia, now in Turkey, his father was a famous maker of scientific instruments, his epithet aṣ-Ṣabi' suggests. Some western historians state that he is of noble origin, like an Arab prince, but traditional Arabic biographers make no mention of this, he worked in Raqqa, a city in north central Syria. One of al-Battānī's best-known achievements in astronomy was the determination of the solar year as being 365 days, 5 hours, 46 minutes and 24 seconds, only 2 minutes and 22 seconds off, he was able to correct some of Ptolemy's results and compiled new tables of the Sun and Moon, long accepted as authoritative.
Some of his measurements were more accurate than ones taken by Copernicus many centuries later. Researchers have ascribed this phenomenon to al-Battānī's location lying closer to the equator so that the ecliptic and the Sun were higher in the sky and therefore less susceptible to atmospheric refraction. Al-Battānī discovered that the direction of the Sun's apogee, as recorded by Ptolemy, was changing.. He introduced independently of the 5th century Indian astronomer Aryabhata, the use of sines in calculation, that of tangents, he calculated the values for the precession of the equinoxes and the obliquity of the ecliptic. He used a uniform rate for precession in his tables, choosing not to adopt the theory of trepidation attributed to his colleague Thabit ibn Qurra. Al-Battānī's work is considered instrumental in the development of astronomy. Copernicus quoted him in the book that initiated the Copernican Revolution, the De Revolutionibus Orbium Coelestium, where his name is mentioned no fewer than 23 times, mentioned him in the Commentariolus.
Al-Battānī was quoted by Tycho Brahe and Riccioli, among others. Kepler and Galileo showed interest in some of his observations, his data continues to be used in geophysics; the major lunar crater Albategnius is named in his honor. In mathematics, al-Battānī produced a number of trigonometrical relationships: tan a = sin a cos a sec a = 1 + tan 2 a He solved the equation sin x = a cos x discovering the formula: sin x = a 1 + a 2 He gives other trigonometric formulae for right-angled triangles such as: b sin = a sin Al-Battānī used al-Marwazi's idea of tangents to develop equations for calculating tangents and cotangents, compiling tables of them, he discovered the reciprocal functions of secant and cosecant, produced the first table of cosecants, which he referred to as a "table of shadows", for each degree from 1° to 90°. Al-Battānī's major work is Kitāb az-Zīj, it was based on Ptolemy's theory, other Greco-Syriac sources, while showing little Indian or Persian influence. In his zij, he provided descriptions of a quadrant instrument.
This book went through many translations to Latin and Spanish, including a Latin translation as De Motu Stellarum by Plato of Tivoli in 1116, reprinted with annotations by Regiomontanus. A reprint appeared at Bologna in 1645; the original MS. is preserved at the Vatican. A treatise of some value by him on astronomical chronology. A ship in Star Trek: Voyager is named after Al-Battānī, known as the USS Al-Batani, which Janeway served on. List of Arab scientists and scholars Zij Al-Battānī sive Albatenii, Opus Astronomicum. Ad fidem codicis escurialensis arabice editum, ed. by Carlo Alfonso Nallino. Milan, Ulrico Hoepli, 1899-1907, 412 + 450 + 288 pp. (anast.: I-III, Lavis 2002 ISBN 978-8888097-26-8 Hartner, Willy. "Al-Battānī, Abū ʿAbd Allāh Muḥammad Ibn Jābir Ibn Sinān al-Raqqī al-Ḥarrānī al–Ṣābi". Dictionary of Scientific Biography. New York: Charles Scribner's Sons. ISBN 978-0-684-10114-9. O'Connor, John J.. Dalen, Benno van. "Battānī: Abū ʿAbd Allāh Muḥammad ibn Jābir ibn Sinān al‐Battānī al‐Ḥarrānī al‐Ṣābiʾ".
In Thomas Hockey. The Biographical Encyclopedia of Astronomers. New Yo
Nasir al-Din al-Tusi
Muhammad ibn Muhammad ibn al-Hasan al-Tūsī, better known as Nasir al-Din Tusi, was a Persian polymath, philosopher, physician and theologian. He established trigonometry as an independent branch of mathematics, he was a Twelver Shia Muslim. Ibn Khaldun claimed Tusi was the greatest of the Persian scholars. Al-Tūsī was born in the city of Tus, Khorasan in the year 1201 and began his studies at an early age. In Hamadan and Tus he studied the Quran, hadith, Ja'fari jurisprudence, philosophy, mathematics and astronomy. Muhammad al-Tūsī's family was Shī‘ah, his father, who died while Muhammad was a only boy, according to his Islamic faith, encouraged his son to study. Al-Tūsī took the acquisition of knowledge seriously and traveled far and wide attending the lectures of renowned scholars. At a young age, he moved to Nishapur to study philosophy under Farid al-Din Damad and mathematics under Muhammad Hasib, he met Attar of Nishapur, the legendary Sufi master, killed by the Mongols, he attended the lectures of Qutb al-Din al-Misri.
In Mosul al-Tūsī studied mathematics and astronomy with Kamal al-Din Yunus, a pupil of Sharaf al-Dīn al-Ṭūsī. He corresponded with Sadr al-Din al-Qunawi, the son-in-law of Ibn Arabi, it seems that the mysticism of the Sufi masters of his time, did not appeal to him; however he composed his own manual of philosophical Sufism in the form of a small booklet entitled Awsaf al-Ashraf "The Attributes of the Illustrious". As the armies of Genghis Khan swept across his homeland, al-Tūsī was employed by the Nizari Ismaili state, his most important contributions to science were made. He was captured after the invasion of Alamut Castle by the Mongol forces. While in Nishapur, al-Tūsī established a reputation for scholarship, he composed over 150 prose works, his diwan is one of the largest by any Muslim author. Writing in Arabic and Persian, Nasir al-Din Tusi treats religious and secular subjects, he translated the works of Euclid, Ptolemy and Theodosius of Bithynia into Arabic. When al-Tūsī convinced the Mongol conqueror Hulegu Khan to build an observatory for purpose of producing accurate astronomical tables, it was the most technically advanced in the world.
Astronomical charts were used in astrological predictions and to calculate the dates of religious festivals, in addition to many other civil and navigational applications. Begun in 1259, the Rasad Khaneh observatory was constructed in Azarbaijan, south of the river Aras and west of Maragheh, the capital of the Ilkhanate Empire. Using the sophisticated measurements taken at the observatory Al-Tusi's accurate astronomical tables of planetary movements are depicted in his book Zij-i ilkhani, his tables calculating the positions of the planets and the names of the stars and his model for the planetary system, the most scientifically advanced of its time, were in use until the development of the heliocentric model in the time of Nicolaus Copernicus. Between Ptolemy and Copernicus, he is considered one of the most eminent astronomers, his famous student Shams ad-Din Al-Bukhari taught the Byzantine scholar Gregory Chioniadis, who had in turn trained the astronomer Manuel Bryennios about 1300 in Constantinople.
The Tusi-couple is a geometrical technique invented by al-Ṭūsī to generate linear motion from the sum of two circular motions and is used in his planetary models. The technique replaced Ptolemy's problematic equant for many planets, but was unable to find a solution to Mercury, solved by Ibn al-Shatir as well as Ali Qushji; the Tusi couple was employed in Ibn al-Shatir's geocentric model and Nicolaus Copernicus' heliocentric Copernican model. He calculated the value for the annual precession of the equinoxes and contributed to the construction and usage of some astronomical instruments including the astrolabe. Al-Ṭūsī noted; however while he too believed in a fixed earth, as did his 16th-century commentator al-Bīrjandī, he insisted only the physical principles based on natural philosophy could be relied upon. Tusi's criticisms of Ptolemy were similar to the arguments used by Copernicus in 1543 to defend the Earth's rotation. On the real essence of the Milky Way, Ṭūsī in his Tadhkira writes: "The Milky Way, i.e. the galaxy, is made up of a large number of small, tightly-clustered stars, which, on account of their concentration and smallness, seem to be cloudy patches.
Because of this, it was likened to milk in color." Three centuries the proof of the Milky Way consisting of many stars came in 1610 when Galileo Galilei used a telescope to study the Milky Way and discovered that it is composed of a huge number of faint stars. Al-Tūsī was a supporter of Avicennian logic, wrote the following commentary on Avicenna's theory of absolute propositions: "What spurred him to this was that in the assertoric syllogistic Aristotle and others sometimes used contradictories of absolute propositions on the assumption that they are absolute; when Avicenna had shown this to be wrong, he wanted to develop a method of construing those examples from Aristotle." Al-Tusi's extensive exposition Treatise on the Quadrilateral, distinguish spherical trigonometry from astronomy. It was in the works of Al-Tusi that trigonometry achieved the status of an independent branch of pure mathematics distinct from
Abu Yūsuf Yaʻqūb ibn ʼIsḥāq aṣ-Ṣabbāḥ al-Kindī was an Arab Muslim philosopher, mathematician and musician. Al-Kindi was the first of the Muslim peripatetic philosophers, is unanimously hailed as the "father of Arab philosophy" for his synthesis and promotion of Greek and Hellenistic philosophy in the Muslim world. Al-Kindi was educated in Baghdad, he became a prominent figure in the House of Wisdom, a number of Abbasid Caliphs appointed him to oversee the translation of Greek scientific and philosophical texts into the Arabic language. This contact with "the philosophy of the ancients" had a profound effect on his intellectual development, led him to write hundreds of original treatises of his own on a range of subjects ranging from metaphysics, ethics and psychology, to medicine, mathematics, astronomy and optics, further afield to more practical topics like perfumes, jewels, dyes, tides, mirrors and earthquakes. In the field of mathematics, al-Kindi played an important role in introducing Indian numerals to the Islamic and Christian world.
Al-Kindi was one of the fathers of cryptography. His book entitled Manuscript on Deciphering Cryptographic Messages gave rise to the birth of cryptanalysis, was the earliest known use of statistical inference, introduced several new methods of breaking ciphers. Using his mathematical and medical expertise, he was able to develop a scale that would allow doctors to quantify the potency of their medication; the central theme underpinning al-Kindi's philosophical writings is the compatibility between philosophy and other "orthodox" Islamic sciences theology. And many of his works deal with subjects; these include the nature of the soul and prophetic knowledge. But despite the important role he played in making philosophy accessible to Muslim intellectuals, his own philosophical output was overshadowed by that of al-Farabi and few of his texts are available for modern scholars to examine. Al-Kindi was born in Kufa to an aristocratic family of the Kinda tribe, descended from the chieftain al-Ash'ath ibn Qays, a contemporary of Muhammad.
The family belonged to the most prominent families of the tribal nobility of Kufa in the early Islamic period, until it lost much of its power following the revolt of Abd al-Rahman ibn Muhammad ibn al-Ash'ath. His father Ishaq was the governor of Kufa, al-Kindi received his preliminary education there, he went to complete his studies in Baghdad, where he was patronized by the Abbasid caliphs al-Ma'mun and al-Mu'tasim. On account of his learning and aptitude for study, al-Ma'mun appointed him to the House of Wisdom, a established centre for the translation of Greek philosophical and scientific texts, in Baghdad, he was well known for his beautiful calligraphy, at one point was employed as a calligrapher by al-Mutawakkil. When al-Ma'mun died, his brother, al-Mu'tasim became Caliph. Al-Kindi's position would be enhanced under al-Mu ` tasim, but on the accession of al-Wāthiq, of al-Mutawakkil, al-Kindi's star waned. There are various theories concerning this: some attribute al-Kindi's downfall to scholarly rivalries at the House of Wisdom.
Henry Corbin, an authority on Islamic studies, says that in 873, al-Kindi died "a lonely man", in Baghdad during the reign of al-Mu'tamid. After his death, al-Kindi's philosophical works fell into obscurity and many of them were lost to Islamic scholars and historians. Felix Klein-Franke suggests a number of reasons for this: aside from the militant orthodoxy of al-Mutawakkil, the Mongols destroyed countless libraries during their invasion. However, he says the most probable cause of this was that his writings never found popularity amongst subsequent influential philosophers such as al-Farabi and Avicenna, who overshadowed him. According to Ibn al-Nadim, al-Kindi wrote at least two hundred and sixty books, contributing to geometry and philosophy, physics. Although most of his books have been lost over the centuries, a few have survived in the form of Latin translations by Gerard of Cremona, others have been rediscovered in Arabic manuscripts, his greatest contribution to the development of Islamic philosophy was his efforts to make Greek thought both accessible and acceptable to a Muslim audience.
Al-Kindi carried out this mission from the House of Wisdom, an institute of translation and learning patronized by the Abbasid Caliphs, in Baghdad. As well as translating many important texts, much of what was to become standard Arabic philosophical vocabulary originated with al-Kindi. In his writings, one of al-Kindi's central concerns was to demonstrate the compatibility between philosophy and natural theology on the one hand, revealed or speculative theology on the other. Despite this, he did make clear that he believed revelation was a superior source of knowledge to