The House of Wisdom

The greatest translator of the Abbasid Translation Movement and the figure more than any other responsible for the transmission of Greek medicine into Arabic. A Nestorian Christian physician, he translated the complete works of Galen — over one hundred texts — along with Hippocrates, Dioscorides, and Plato, often working first into Syriac and then into Arabic to ensure precision. His Ten Treatises on the Eye was the most systematic account of ophthalmology produced in the medieval world. He directed the translation bureau at the House of Wisdom under the Caliph al-Mutawakkil.

Mathematician whose Kitāb al-mukhtasar fī ḥisāb al-jabr wal-muqābala (“The Compendious Book on Calculation by Completion and Balancing”) gave the world the word “algebra” — from al-jabr, the operation of transposing terms. His separate work on Hindu-Arabic numerals, translated into Latin as Algoritmi de numero Indorum, gave the world the word “algorithm” from the Latinisation of his name. He worked at the House of Wisdom under al-Ma’mūn and also produced an influential revision of Ptolemy’s geography.

A Sabian from Harran who became one of the most prolific scholars at the House of Wisdom, producing translations of Archimedes, Apollonius, Euclid, and Ptolemy as well as original work in number theory, the geometry of the parabola, and the theory of amicable numbers. He extended Pythagoras’s theorem to a general statement about any triangle, anticipating later developments in trigonometry. His translations of Archimedes were among the primary conduits through which Archimedean mathematics reached the Latin West.

Astronomer who produced the most accurate observations of the sun, moon, and planets made in the medieval world, and who used them to correct Ptolemy. His Zīj al-Sabī calculated the solar year to within two minutes of the modern value, determined the precession of the equinoxes, and made extensive use of trigonometric functions in ways that substantially advanced the mathematical tools available to astronomy. He was known in the Latin West as Albategnius; Copernicus cited him by name in De revolutionibus.

The first philosopher to write in Arabic — a title he earned both chronologically and in terms of ambition. Al-Kindī argued that Greek philosophy and Islamic theology were compatible, that reason and revelation addressed different aspects of the same truth, and that the philosophical inheritance of Greece was the common property of all rational minds regardless of religion. He wrote on optics, cryptography, music theory, and medicine as well as metaphysics. His treatise on cryptanalysis is the earliest known text on frequency analysis, making him also the founder of that discipline.

Known as “the Second Teacher” — Aristotle being the first — Al-Fārābī was the philosopher who most systematically reconciled Aristotelian and Neoplatonic philosophy with Islamic thought. His Opinions of the Inhabitants of the Virtuous City is a political philosophy in the Platonic tradition, describing the conditions for a just society governed by a philosopher-prophet. He also wrote the most comprehensive account of music theory in the medieval Islamic world. His commentaries on Aristotle were so authoritative that Avicenna said he understood Aristotle’s Metaphysics only after reading Al-Fārābī’s commentary.

The most influential philosopher-physician of the medieval world, whose Kitāb al-shāfā (“Book of Healing”) is the most comprehensive encyclopaedia of philosophy and science produced in the Islamic world, and whose Qānūn fī al-ṭibb (“Canon of Medicine”) remained the standard medical textbook in Europe and the Islamic world until the seventeenth century. His “Flying Man” thought experiment — a human being suspended in space, deprived of all sensory input: would they still be aware of themselves? — is one of the earliest formulations of what modern philosophy calls the problem of self-awareness.

Physician and polymath who was the greatest clinician of the medieval world. His Kitāb al-Ḥāwī (“The Comprehensive Book”), a compilation of his clinical notes in twenty-three volumes, is one of the largest medical works ever written. His monograph distinguishing smallpox from measles — the first clinical description of either disease — remained the most authoritative account of both conditions for seven centuries. He was also a significant alchemist who argued, against Aristotle, that matter has specific properties that cannot be transformed by the manipulation of qualities alone.

The founder of modern optics, whose Kitāb al-Manāẓir (“Book of Optics”) established the intromission theory of vision — that the eye receives light from objects rather than emitting rays toward them — and provided the mathematical account of reflection, refraction, and image formation in mirrors and lenses that Newton and Kepler would later build on. He also described the camera obscura, explained the apparent enlargement of celestial bodies near the horizon, and was one of the first scholars to insist that natural philosophy must rest on systematic experiment rather than a priori reasoning.

The most universal scholar of the medieval Islamic world: mathematician, astronomer, physicist, geographer, historian, linguist, and anthropologist. He learned Sanskrit to read Indian scientific texts in the original and produced Kitāb fī taḥqīq mā li-l-Hind (“Researches on India”) — the most accurate and sympathetic account of Indian civilisation produced by any non-Indian scholar before the modern era. He calculated the radius of the Earth to within 1% of the modern value using a method involving the measurement of a mountain’s height, and described the possibility of a landmass across the Atlantic five centuries before Columbus.