Islamic Golden Age

The various Quranic injunctions and Hadith (or actions of Muhammad), which place values on education and emphasize the importance of acquiring knowledge, played a vital role in influencing the Muslims of this age in their search for knowledge and the development of the body of science.[15][16][17]

The Islamic Empire heavily patronized scholars. The money spent on the Translation Movement for some translations is estimated to be equivalent to about twice the annual research budget of the United Kingdom's Medical Research Council.[18] The best scholars and notable translators, such as Hunayn ibn Ishaq, had salaries that are estimated to be the equivalent of professional athletes today.[18] The House of Wisdom was a library established in Abbasid-era Baghdad, Iraq by Caliph al-Mansur[19] in 825 modeled after the academy of Jundishapur.

During this period, the Muslims showed a strong interest in assimilating the scientific knowledge of the civilizations that had been conquered. Many classic works of antiquity that might otherwise have been lost were translated from Greek, Syriac, Middle Persian, and Sanskrit into Syriac and Arabic, some of which were later in turn translated into other languages like Hebrew and Latin.[4]

The Christian physician Hunayn ibn Ishaq lead the translation of works

Christians, especially the adherents of the Church of the East (Nestorians), contributed to Islamic civilization during the reign of the Umayyads and the Abbasids by translating works of Greek philosophers and ancient science to Syriac and afterwards to Arabic.[20][21] They also excelled in many fields, in particular philosophy, science (such as Hunayn ibn Ishaq,[22][23] Yusuf Al-Khuri,[24] Al Himsi,[25] Qusta ibn Luqa,[26] Masawaiyh,[27][28] Patriarch Eutychius,[29] and Jabril ibn Bukhtishu[30]) and theology. For a long period of time the personal physicians of the Abbasid Caliphs were often Assyrian Christians.[31][32] Among the most prominent Christian families to serve as physicians to the caliphs were the Bukhtishu dynasty.[33][34] Throughout the 4th to 7th centuries, Christian scholarly work in the Greek and Syriac languages was either newly translated or had been preserved since the Hellenistic period. Among the prominent centers of learning and transmission of classical wisdom were Christian colleges such as the School of Nisibis[35] and the School of Edessa,[36] the pagan center of learning in Harran,[37] and the renowned hospital and medical Academy of Gondishapur, which was the intellectual, theological and scientific center of the Church of the East.[38][39][40] Many scholars of the House of Wisdom were of Christian background and it was led by Christian physician Hunayn ibn Ishaq, with the support of Byzantine medicine. Many of the most important philosophical and scientific works of the ancient world were translated, including the work of Galen, Hippocrates, Plato, Aristotle, Ptolemy and Archimedes.[41]

Persians also were a notably high proportion of scientists who contributed to the Islamic Golden Age. According to Bernard Lewis: "Culturally, politically, and most remarkable of all even religiously, the Persian contribution to this new Islamic civilization is of immense importance. The work of Iranians can be seen in every field of cultural endeavor, including Arabic poetry, to which poets of Iranian origin composing their poems in Arabic made a very significant contribution."[42]

While cultural influence used to radiate outward from Baghdad, after the Mongol destruction of the Abbasid Caliphate, Arab influence decreased.[43] Iran and Central Asia, benefiting from increased cross-cultural access to East Asia under Mongol rule, flourished and developed more distinctively from Arab influence, such as the Timurid Renaissance under the Timurid dynasty.[44]

A manuscript written on paper during the Abbasid Era.

With a new and easier writing system, and the introduction of paper, information was democratized to the extent that, for probably the first time in history, it became possible to make a living from only writing and selling books.[45] The use of paper spread from China into Muslim regions in the eighth century through mass production in Samarkand and Khorasan,[46] arriving in Al-Andalus on the Iberian peninsula (modern Spain and Portugal) in the 10th century. It was easier to manufacture than parchment, less likely to crack than papyrus, and could absorb ink, making it difficult to erase and ideal for keeping records. Islamic paper makers devised assembly-line methods of hand-copying manuscripts to turn out editions far larger than any available in Europe for centuries.[47] It was from these countries that the rest of the world learned to make paper from linen.[48]

Ibn Sina argued his "Floating man" thought experiment concerning self-awareness, in which a man prevented of sense experience by being blindfolded and free falling would still be aware of his existence.[68]

In epistemology, Ibn Tufail wrote the novel Hayy ibn Yaqdhan and in response Ibn al-Nafis wrote the novel Theologus Autodidactus. Both were concerning autodidacticism as illuminated through the life of a feral child spontaneously generated in a cave on a desert island.

Geometric patterns: an archway in the Sultan's lodge in the Ottoman Green Mosque in Bursa, Turkey (1424), its girih strapwork forming 10-point stars and pentagons

Persian mathematician Muḥammad ibn Mūsā al-Khwārizmī played a significant role in the development of algebra, arithmetic and Hindu-Arabic numerals. He has been described as the father[69][70] or founder[71][72] of algebra.

Another Persian mathematician, Omar Khayyam, is credited with identifying the foundations of Analytic geometry. Omar Khayyam found the general geometric solution of the cubic equation. His book Treatise on Demonstrations of Problems of Algebra (1070), which laid down the principles of algebra, is part of the body of Persian mathematics that was eventually transmitted to Europe.[73]

Yet another Persian mathematician, Sharaf al-Dīn al-Tūsī, found algebraic and numerical solutions to various cases of cubic equations.[74] He also developed the concept of a function.[75]

Islamic art makes use of geometric patterns and symmetries in many of its art forms, notably in girih tilings. These are formed using a set of five tile shapes, namely a regular decagon, an elongated hexagon, a bow tie, a rhombus, and a regular pentagon. All the sides of these tiles have the same length; and all their angles are multiples of 36° (π/5 radians), offering fivefold and tenfold symmetries. The tiles are decorated with strapwork lines (girih), generally more visible than the tile boundaries. In 2007, the physicists Peter Lu and Paul Steinhardt argued that girih from the 15th century resembled quasicrystalline Penrose tilings.[76][77][78][79] Elaborate geometric zellige tilework is a distinctive element in Moroccan architecture.[80] Muqarnas vaults are three-dimensional but were designed in two dimensions with drawings of geometrical cells.[81]

Jamshīd al-Kāshī's estimate of pi would not be surpassed for 180 years.[82]

A triangle labelled with the components of the law of sines. Capital A, B and C are the angles, and lower-case a, b, c are the sides opposite them. (a opposite A, etc.)

Ibn Muʿādh al-Jayyānī is one of the several Islamic mathematicians on whom the law of sines is attributed; he wrote "The Book of Unknown Arcs of a Sphere" in the 11th century. This formula relates the lengths of the sides of any triangle, rather than only right triangles, to the sines of its angles.[83] According to the law,

${\displaystyle {\frac {\sin A}{a}}\,=\,{\frac {\sin B}{b}}\,=\,{\frac {\sin C}{c}}.}$

where a, b, and c are the lengths of the sides of a triangle, and A, B, and C are the opposite angles (see figure).

Ibn al-Haytham (Alhazen) discovered the sum formula for the fourth power, using a method that could be generally used to determine the sum for any integral power. He used this to find the volume of a paraboloid. He could find the integral formula for any polynomial without having developed a general formula.[84]

Ibn al-Haytham (Alhazen) was a significant figure in the history of scientific method, particularly in his approach to experimentation,[85][86][87][88] and has been described as the "world's first true scientist".[89]

Avicenna made rules for testing the effectiveness of drugs, including that the effect produced by the experimental drug should be seen constantly or after many repetitions, to be counted.[90] The physician Rhazes was an early proponent of experimental medicine and recommended using control for clinical research. He said: "If you want to study the effect of bloodletting on a condition, divide the patients into two groups, perform bloodletting only on one group, watch both, and compare the results."[91]

Astronomy in Islam was able to grow greatly because of several key factors. One factor was geographical: the Islamic world was close to the ancient lands of the Greeks, which held valuable ancient knowledge of the heavens in Greek manuscripts.[92] During the new Abbasid Dynasty after the movement of the capital in 762 AD to Baghdad, translators were sponsored to translate Greek texts into Arabic.[92] This translation period led to many major scientific works from Galen, Ptolemy, Aristotle, Euclid, Archimedes, and Apollonius being translated into Arabic.[92] From these translations previously lost knowledge of the cosmos was now being used to advance current astrological thinkers. The second key factor of astronomy's growth was the religious observances followed by Muslims which expected them to pray at exact times during the day.[92] These observances in timekeeping led to many questions in previous Greek mathematical astronomy, especially their timekeeping.[92]

Astrolabe with Quranic inscriptions from Iran, dated 1060 AH (1650-51 AD)

The Astrolabe was a Greek invention which was an important piece of Arabic astronomy. An Astrolabe is a handheld two-dimensional model of the sky which can solve problems of spherical astronomy.[92] It is made up of lines of altitude and azimuth with an index, horizon, hour circle, zenith, Rete, star pointer, and equator to accurately show where the stars are at that given moment.[92] Use of the astrolabe is best expressed in Al-Farghani's treatise on the astrolabe due to the mathematical way he applied the instrument to astrology, astronomy, and timekeeping.[92] The earliest known Astrolabe in existence today comes from the Islamic period. It was made by Nastulus in 927-28 AD and is now a treasure of the Kuwait National Museum.[92]

In about 964 AD, the Persian astronomer Abd al-Rahman al-Sufi, writing in his Book of Fixed Stars, described a "nebulous spot" in the Andromeda constellation, the first definitive reference to what is now known to be the Andromeda Galaxy, the nearest spiral galaxy to the Milky Way.

One of the largest advances in Islamic astronomy was the rejection of the Ptolemaic system of the planets. This system developed by Ptolemy placed the sun, moon, and other planets in orbit around the Earth.[92] Ptolemy thought that the planets moved on circles called epicycles and that their centers rode on deferents. The deferents were eccentric, and the angular motion of a planet was uniform around the equant which was a point opposite the deferent center.[92] Simply, Ptolemy's models were a mathematical system for predicting the positions of the planets. One of the first to criticize this model was Ibn al-Haytham, a leader of physics in the 11th century in Cairo. Then in the 13th century Nasir al-Din al-Tusi constructed the Maragha Observatory in what is today Iran.[92] Al-Tusi found the equant dissatisfying and replaced it by adding a geometrical technique called a Tusi-couple, which generates linear motion from the sum of two circular motions. Then, Ibn al-Shatir who was working in Damascus in 1350 AD employed the Tusi-couple to successfully eliminate the equant as well as other objectionable circles that Ptolemy had used.[93] This new model properly aligned the celestial spheres and was mathematically sound.[92] This development by Ibn al-Shatir, as well as the Maragha astronomers remained relatively unknown in medieval Europe.[92]

The Tusi couple was later employed in Ibn al-Shatir's geocentric model and Nicolaus Copernicus' heliocentric model although it is not known who the intermediary is or if Copernicus rediscovered the technique independently. The names for some of the stars used, including Betelgeuse, Rigel, Vega, Aldebaran, and Fomalhaut are several of the names that come directly from Arabic origins or are the translations of Ptolemy's Greek descriptions which are still in use today.[92]

Tusi couple

Alhazen played a role in the development of optics. One of the prevailing theories of vision in his time and place was the emission theory supported by Euclid and Ptolemy, where sight worked by the eye emitting rays of light, and the other was the Aristotelean theory that sight worked when the essence of objects flows into the eyes. Alhazen correctly argued that vision occurred when light, traveling in straight lines, reflects off an object into the eyes. Al-Biruni wrote of his insights into light, stating that its velocity must be immense when compared to the speed of sound.[94]

The early Islamic period saw the establishment of some of the longest lived theoretical frameworks in alchemy and chemistry. The sulfur-mercury theory of metals, first attested in pseudo-Apollonius of Tyana's Sirr al-khalīqa ("The Secret of Creation", c. 750–850) and in the Arabic writings attributed to Jābir ibn Ḥayyān (written c. 850–950),[95] would remain the basis of all theories of metallic composition until the eighteenth century.[96] Likewise, the Emerald Tablet, a compact and cryptic text that all later alchemists up to and including Isaac Newton (1642–1727) would regard as the foundation of their art, first occurs in the Sirr al-khalīqa and in one of the works attributed to Jābir.[97]

Substantial advances were also made in practical chemistry. The works attributed to Jābir, and those of the Persian alchemist and physician Abū Bakr al-Rāzī (c. 865–925), contain the earliest known systematic classifications of chemical substances.[98] However, alchemists were not only interested in identifying and classifying chemical substances, but also in artificially creating them.[99] Significant examples from the medieval Islamic world include the synthesis of ammonium chloride from organic substances as described in the works attributed to Jābir,[100] and Abū Bakr al-Rāzī's experiments with vitriol, which would eventually lead to the discovery of mineral acids like sulfuric acid and nitric acid by thirteenth century Latin alchemists such as pseudo-Geber.[98]

Al-Biruni (973–1048) estimated the radius of the earth as 6339.6 km (modern value is c. 6,371 km), the best estimate at that time.[101]

The eye, according to Hunain ibn Ishaq. From a manuscript dated circa 1200.

In the cardiovascular system, Ibn al-Nafis in his Commentary on Anatomy in Avicenna's Canon was the first known scholar to contradict the contention of the Galen School that blood could pass between the ventricles in the heart through the cardiac inter-ventricular septum that separates them, saying that there is no passage between the ventricles at this point.[102] Instead, he correctly argued that all the blood that reached the left ventricle did so after passing through the lung.[102] He also stated that there must be small communications, or pores, between the pulmonary artery and pulmonary vein, a prediction that preceded the discovery of the pulmonary capillaries of Marcello Malpighi by 400 years. The Commentary was rediscovered in the twentieth century in the Prussian State Library in Berlin; whether its view of the pulmonary circulation influenced scientists such as Michael Servetus is unclear.[102]

In the nervous system, Rhazes stated that nerves had motor or sensory functions, describing 7 cranial and 31 spinal cord nerves. He assigned a numerical order to the cranial nerves from the optic to the hypoglossal nerves. He classified the spinal nerves into 8 cervical, 12 thoracic, 5 lumbar, 3 sacral, and 3 coccygeal nerves. He used this to link clinical signs of injury to the corresponding location of lesions in the nervous system.[103]

Modern commentators have likened medieval accounts of the "struggle for existence" in the animal kingdom to the framework of the theory of evolution. Thus, in his survey of the history of the ideas which led to the theory of natural selection, Conway Zirkle noted that al-Jahiz was one of those who discussed a "struggle for existence", in his Kitāb al-Hayawān (Book of Animals), written in the 9th century.[104] In the 13th century, Nasir al-Din al-Tusi believed that humans were derived from advanced animals, saying, "Such humans [probably anthropoid apes][105] live in the Western Sudan and other distant corners of the world. They are close to animals by their habits, deeds and behavior."[105] In 1377, Ibn Khaldun in his Muqaddimah stated, "The animal kingdom was developed, its species multiplied, and in the gradual process of Creation, it ended in man and arising from the world of the monkeys."[106]

Entrance to the Qalawun complex which housed the notable Mansuri hospital in Cairo

The earliest known Islamic hospital was built in 805 in Baghdad by order of Harun Al-Rashid, and the most important of Baghdad's hospitals was established in 982 by the Buyid ruler 'Adud al-Dawla.[114] The best documented early Islamic hospitals are the great Syro-Egyptian establishments of the 12th and 13th centuries.[114] By the tenth century, Baghdad had five more hospitals, while Damascus had six hospitals by the 15th century and Córdoba alone had 50 major hospitals, many exclusively for the military.[115]

The typical hospital was divided into departments such as systemic diseases, surgery, and orthopedics, with larger hospitals having more diverse specialties. "Systemic diseases" was the rough equivalent of today's internal medicine and was further divided into sections such as fever, infections and digestive issues. Every department had an officer-in-charge, a presiding officer and a supervising specialist. The hospitals also had lecture theaters and libraries. Hospitals staff included sanitary inspectors, who regulated cleanliness, and accountants and other administrative staff.[115] The hospitals were typically run by a three-man board comprising a non-medical administrator, the chief pharmacist, called the shaykh saydalani, who was equal in rank to the chief physician, who served as mutwalli (dean).[90] Medical facilities traditionally closed each night, but by the 10th century laws were passed to keep hospitals open 24 hours a day.[116]

For less serious cases, physicians staffed outpatient clinics. Cities also had first aid centers staffed by physicians for emergencies that were often located in busy public places, such as big gatherings for Friday prayers. The region also had mobile units staffed by doctors and pharmacists who were supposed to meet the need of remote communities. Baghdad was also known to have a separate hospital for convicts since the early 10th century after the vizier 'Ali ibn Isa ibn Jarah ibn Thabit wrote to Baghdad's chief medical officer that "prisons must have their own doctors who should examine them every day". The first hospital built in Egypt, in Cairo's Southwestern quarter, was the first documented facility to care for mental illnesses. In Aleppo's Arghun Hospital, care for mental illness included abundant light, fresh air, running water and music.[115]

Medical students would accompany physicians and participate in patient care. Hospitals in this era were the first to require medical diplomas to license doctors.[117] The licensing test was administered by the region's government appointed chief medical officer. The test had two steps; the first was to write a treatise, on the subject the candidate wished to obtain a certificate, of original research or commentary of existing texts, which they were encouraged to scrutinize for errors. The second step was to answer questions in an interview with the chief medical officer. Physicians worked fixed hours and medical staff salaries were fixed by law. For regulating the quality of care and arbitrating cases, it is related that if a patient dies, their family presents the doctor's prescriptions to the chief physician who would judge if the death was natural or if it was by negligence, in which case the family would be entitled to compensation from the doctor. The hospitals had male and female quarters while some hospitals only saw men and other hospitals, staffed by women physicians, only saw women.[115] While women physicians practiced medicine, many largely focused on obstetrics.[118]

Hospitals were forbidden by law to turn away patients who were unable to pay.[116] Eventually, charitable foundations called waqfs were formed to support hospitals, as well as schools.[116] Part of the state budget also went towards maintaining hospitals.[115] While the services of the hospital were free for all citizens[116] and patients were sometimes given a small stipend to support recovery upon discharge, individual physicians occasionally charged fees.[115] In a notable endowment, a 13th-century governor of Egypt Al-Mansur Qalawun ordained a foundation for the Qalawun hospital that would contain a mosque and a chapel, separate wards for different diseases, a library for doctors and a pharmacy[119] and the hospital is used today for ophthalmology.[115] The Qalawun hospital was based in a former Fatimid palace which had accommodation for 8,000 people – [120] "it served 4,000 patients daily." The waqf stated,

... The hospital shall keep all patients, men and women, until they are completely recovered. All costs are to be borne by the hospital whether the people come from afar or near, whether they are residents or foreigners, strong or weak, low or high, rich or poor, employed or unemployed, blind or sighted, physically or mentally ill, learned or illiterate. There are no conditions of consideration and payment, none is objected to or even indirectly hinted at for non-payment.[119]

Arabic scholars used their natural and cultural resources to contribute to the strong development of pharmacology. They believed that God had provided the means for a cure for every disease. However, there was confusion about the nature of some ancient plants that existed during this time.[121]

A prominent figure that was influential in the development of pharmacy used the name Yūhannā ibn Māsawaiyh (circa 777-857). He was referred to as "The Divine Mesue" and "The Prince of Medicine" by European scholars. Māsawaiyh led the first private medical school in Baghdad and wrote three major pharmaceutical treatises.[122] These treatises consisted of works over compound medicines, humors, and pharmaceutical recipes that provided instructions on how they were to be prepared. In the Latin West, these works were typically published together under the title "Opera Medicinalia" and were broken up into "De simplicubus", "Grabadin", and "Canones universales". Although Māsawaiyh's influence was so significant that his writings became the most dominant source of pharmaceutical writings,[122] his exact identity remains unclear.[122]

In the past, all substances that were to be introduced into, on or near the human body were labeled as medicine, ranging from drugs, food, beverages, even perfumes to cosmetics. The earliest distinction between medicine and pharmacy as disciplines began in the seventh century, when pharmacists and apothecaries appeared in the first hospitals. Demand for drugs increased as the population increased. By the ninth century where pharmacy was established as an independent and well-defined profession by Muslim scholars. It is said by many historians that the opening of the first private pharmacy in the eighth century marks the independence of pharmacy from medicine.[121]

The emergence of medicine and pharmacy within the Islamic caliphate by the ninth century occurred at the same time as rapid expansion of many scientific institutions, libraries, schools, hospitals and then pharmacies in many Muslim cities. The rise of alchemy during the ninth century also played a vital role for early pharmacological development. While Arab pharmacists were not successful in converting non-precious metals into precious metals, their works giving details of techniques and lab equipment were major contributors to the development of pharmacy. Chemical techniques such as distillation, condensation, evaporation and pulverization were often used.

The Qur'an provided the basis for the development of professional ethics where the rise of ritual washing also influenced the importance of hygiene in pharmacology. Pharmacies were periodically visited by government inspectors called muhtasib, who checked to see that the medicines were mixed properly, not diluted and kept in clean jars. Work done by the muhtasib was carefully outlined in manuals that explained ways of examining and recognizing falsified drugs, foods and spices. It was forbidden for pharmacists to perform medical treatment without the presence of a physician, while physicians were limited to the preparation and handling of medications. It was feared that recipes would fall into the hands of someone without the proper pharmaceutical training. Licenses were required to run private practices. Violators were fined or beaten.

The theory of Humorism was largely dominant during this time. Arab physician Ibn Zuhr provided proof that scabies is caused by the itch mite and that it can be cured by removing the parasite without the need for purging, bleeding or other treatments called for by humorism, making a break with the humorism of Galen and Avicenna.[118] Rhazes differentiated through careful observation the two diseases smallpox and measles, which were previously lumped together as a single disease that caused rashes.[123] This was based on location and the time of the appearance of the symptoms and he also scaled the degree of severity and prognosis of infections according to the color and location of rashes.[124] Al-Zahrawi was the first physician to describe an ectopic pregnancy, and the first physician to identify the hereditary nature of haemophilia.[125]

On hygienic practices, Rhazes, who was once asked to choose the site for a new hospital in Baghdad, suspended pieces of meat at various points around the city, and recommended building the hospital at the location where the meat putrefied the slowest.[91]

Al-Razi is sometimes called the "Father of pediatrics" for writing the monograph, The Diseases of Children treating paediatrics as an independent field of medicine.[126]

For Islamic scholars, Indian and Greek physicians and medical researchers Sushruta, Galen, Mankah, Atreya, Hippocrates, Charaka, and Agnivesha were pre-eminent authorities.[127] In order to make the Indian and Greek tradition more accessible, understandable, and teachable, Islamic scholars ordered and made more systematic the vast Indian and Greco-Roman medical knowledge by writing encyclopedias and summaries. Sometimes, past scholars were criticized, like Rhazes who criticized and refuted Galen's revered theories, most notably, the Theory of Humors and was thus accused of ignorance.[91] It was through 12th-century Arabic translations that medieval Europe rediscovered Hellenic medicine, including the works of Galen and Hippocrates, and discovered ancient Indian medicine, including the works of Sushruta and Charaka.[128][129] Works such as Avicenna's The Canon of Medicine were translated into Latin and disseminated throughout Europe. During the 15th and 16th centuries alone, The Canon of Medicine was published more than thirty-five times. It was used as a standard medical textbook through the 18th century in Europe.[130]

Al-Zahrawi was a tenth century Arab physician. He is sometimes referred to as the "Father of surgery".[131] He describes what is thought to be the first attempt at reduction mammaplasty for the management of gynaecomastia[131] and the first mastectomy to treat breast cancer.[118] He is credited with the performance of the first thyroidectomy.[132] He wrote three textbooks on surgery, including Manual of Medial Practitioners which contains a catalog of 278 instruments used in surgery [133]

In the thirteenth century, Ibn al-Quff was a physician and surgeon who published numerous books, commentaries, treatises on surgery. Most notably, he wrote Basics in the Art of Surgery, a general medical manual covering anatomy, drugs therapy and surgical care, which was by far the largest Arabic text on surgery during the entire medieval period.[134]

The diffusion of sugarcane from the Indian subcontinent to Spain during Islamic rule.

The Arabs of Al-Andalus exerted a large impact on Spanish agriculture, including the restoration of Roman-era aqueducts and irrigation channels, as well as the introduction of new technologies such as the acequias (derived from the qanats of Persia) and Persian gardens (such as at the Generalife). In Spain and Sicily, the Arabs introduced crops and foodstuffs from the Persia and India such as rice, sugarcane, oranges, lemons, bananas, saffron, carrots, apricots and eggplants, as well as restoring cultivation of olives and pomegranates from Greco-Roman times. The Palmeral of Elche in southern Spain is a UNESCO World Heritage site that is emblematic of the Islamic agricultural legacy in Europe.

The 13th century Seljuq poet Rumi wrote some of the finest poetry in the Persian language and remains one of the best selling poets in America.[138][139] Other famous poets of the Persian language include Hafez (whose work was read by William Jones, Thoreau, Goethe, Ralph Waldo Emerson and Friedrich Engels), Saadi (whose poetry was cited extensively by Goethe, Hegel and Voltaire), Ferdowsi, Omar Khayyam and Amir Khusrow.

One Thousand and One Nights, an anthology of Middle Eastern folk tales compiled in the Arabic language during the time of the Abbasid Caliphate, has had a large influence on Western and Middle Eastern literature and popular culture with such classics as Aladdin, Ali Baba and the Forty Thieves and Sinbad the Sailor. The folk-tale 'Sinbad the Sailor' even draws inspiration directly from Hellenistic literature like the Homeric epics (translated from Greek to Arabic in the 8th century CE) and Alexander Romances (tales of Alexander the Great popular in Europe, the Middle East and India).

Marquetry and tile-top table, 1560

Calligraphy, an essential aspect of written Arabic, developed in manuscripts and architectural decoration. This form of visual art can be found adorning the walls of palaces, the interior and domes of mosques as well as the surrounding structure of minbars.[140] Calligraphy would use a variety of stylised and standardised scripts, two major scripts among them being kufic and naskh. Ceramics, metalwork and glassware were also brilliantly decorated with geometric patterns and vibrant colors.[141]

Manuscript illumination was an important art, and Persian miniature painting flourished in the Persianate world, and went on to influence miniature art in the Ottoman and Mughal court between the 16th–17th centuries.[142][143] Very few surviving records of wall painting exists, especially ones that represented the human face. A rare example of this are the early 9th-century fragments from the ruins of the Dar al-Khilafah palace at Samarra from the Abbasid period. These are fragments of larger wall paintings depicting harem women, period-era clothing and animals.[144]

The ninth and tenth centuries saw a flowering of Arabic music. Philosopher and esthete Al-Farabi,[145] at the end of the ninth century, established the foundations of modern Arabic music theory, based on the maqammat, or musical modes. His work was based on the music of Ziryab, the court musician of Andalusia. Ziryab was a renowned polymath, whose contributions to western civilization included formal dining, haircuts, chess, and more, in addition to his dominance of the world musical scene of the ninth century.[146]

The Sumerians and Akkadians, the Greeks, and the Persians all used math to create notes used on lutes and lyres and other stringed instruments. Using the idea that a plucked or bowed string produces a note, they noticed the difference in tone when a string is stopped. "The great discovery" was hearing the double octave, that halving a string produces a note one octave above the string.[147] Written as a ratio 2:1.[147]

They measured the ratios of string lengths on one side and the other of where the string was pressed, creating ratios. Those ratios allowed them to compare sounds, for example third intervals, fourths, fifths. They were able to tune one string against another in those intervals on lutes, lyres, harps, zithers. Lutes gave them the further ability to create those intervals on a single string, by adding frets at mathematically spaced distances, based on the ratios. Unlike modern instruments, where frets may be permanently fixed into the neck, as on a guitar, the older instruments used gut strings tied around the neck for frets, and this made their instruments adjustable. Early musicians could tune their instruments to different modes. Lute players could tune the strings to different intervals, and could further adjust the frets for the modes.

Drawing of a lute by Safi al-Din from a 1333 copy of his book, Kitab al-Adwār. The oldest copy dates to 1296.

The mixing cultures of Central Asia and Arabia produced several thinkers who wrote about music, including something about the lute in their works, including Al-Kindi (c. 801 – c. 873), Ziryab (789–857), Al-Farabi (c. 872 – c. 950), Avicenna (c. 980 – 1037), and Safi al-Din al-Urmawi (1216–1294). They wrote in Arabic, what had become the useful lingua-Franca of their time, and took part in Muslim society and culture. However they were brought up in Central Asia.

The Arabs had a musical scale, described by al-Farabi, in use by some through the 13th century A.D.[148] That tanbar scale, which divided the string into "40 equal parts" may have been a leftover from Babylon and Assyria.[148] However, the Arabs traded with and conquered the Persians, and they adopted Persian scales for their lutes, just as they adopted Persian short-necked lutes.[148]

Ziryab moved from Baghdad to al-Andalus, where he set up a school of music and was one of the first to add a fifth string or course to oud, "between 822 and 852).[149] Al-Andalus, where he settled would become a center of musical instrument development for Europe.

Al-Kindi was a polymath who wrote as many as 15 music-related treatises. He was among the first to apply Greek musical theory to Central Asian-Arabian short lutes.[149] He added semi-tones between the nut and the first string.[149] He also added a fifth string to his oud in the east, as Ziryab had done in the west.[149]

Al-Farabi "fully incorporated the works of Aristoxenus and Ptolemy into his theory of tetrachords", and wrote among books in many subjects, the Kitab al-Musiqa al-Kabir, the Major Book of Music, in which he detailed how to tune an oud, using mathematical ratios.[150] He gave instruction for both 10 frets and 12, telling where to place the tied (and moveable) gut-string frets on the neck.[150] His way of tuning allowed a "12-fret 'ud tuning — which results ... 'double-octave' scale", with 22 notes in each octave.[150]

The Great Mosque of Kairouan (in Tunisia), the ancestor of all the mosques in the western Islamic world excluding Turkey and the Balkans,[151] is one of the best preserved and most significant examples of early great mosques. Founded in 670, it dates in its present form largely from the 9th century.[152] The Great Mosque of Kairouan is constituted of a three-tiered square minaret, a large courtyard surrounded by colonnaded porticos, and a huge hypostyle prayer hall covered on its axis by two cupolas.[151]

The Great Mosque of Samarra in Iraq was completed in 847. It combined the hypostyle architecture of rows of columns supporting a flat base, above which a huge spiralling minaret was constructed.

The beginning of construction of the Great Mosque at Cordoba in 785 marked the beginning of Islamic architecture in Spain and Northern Africa. The mosque is noted for its striking interior arches. Moorish architecture reached its peak with the construction of the Alhambra, the magnificent palace/fortress of Granada, with its open and breezy interior spaces adorned in red, blue, and gold. The walls are decorated with stylized foliage motifs, Arabic inscriptions, and arabesque design work, with walls covered in geometrically patterned glazed tiles.

Many traces of Fatimid architecture exist in Cairo today, the most defining examples include the Al Azhar University and the Al Hakim mosque.

Economic historian Joel Mokyr has argued that Islamic philosopher al-Ghazali (1058–1111), the author of The Incoherence of the Philosophers, "was a key figure in the decline in Islamic science" and that this led to a cultural shift shunning away from scientific thinking.[153] However, it is argued that al-Ghazali was instead an admirer and adherent of philosophy but was criticizing the use of philosophy in religious matters only.[154] Additionally, Saliba (2007) has pointed out that the golden age did not slow down after al-Ghazali, who lived in the 11th century,[155][156] while others extend the golden age to around the 16th[3] to 17th centuries.[157][158][159]

Ahmad Y. al-Hassan has rejected the thesis that lack of creative thinking was a cause, arguing that science was always kept separate from religious argument; he instead analyzes the decline in terms of economic and political factors, drawing on the work of the 14th-century writer Ibn Khaldun.[3]

Several other contemporary scholars have analysed the decline in terms of political and economic factors.[1][2] Current research has led to the conclusion that "the available evidence is consistent with the hypothesis that an increase in the political power of these elites caused the observed decline in scientific output."[160] The decline could be part of a larger trend where the non-Western world fell behind the West in the Great Divergence. In 1206, Genghis Khan established the Mongol Empire which, during the 13th century, conquered most of the Eurasian land mass, including China in the east and much of the old Islamic caliphate (as well as Kievan Rus') in the west. The destruction of Baghdad and the House of Wisdom by Hulagu Khan in 1258 has been seen by some as the end of the Islamic Golden Age.[161] However, while cultural influence used to radiate outward from Baghdad, after the fall of Baghdad, Iran and Central Asia saw a cultural flourishing by benefiting from increased cross-cultural access to East Asia under Mongol rule.[43][44]