AlKhwarizmi
Muḥammad ibn Mūsā alKhwārizmī  

محمد بن موسى خوارزمی  
Born  c. 780 
Died  c. 850^{[2]}^{[3]} (aged ~70) Abbasid Caliphate 
Nationality  Persian 
Occupation  Head of the House of Wisdom in Baghdad (appt. c. 820) 
Academic work  
Era  Islamic Golden Age 
Main interests  
Notable works 

Notable ideas  Treatises on algebra and the Hindu–Arabic numeral system 
Influenced  Abu Kamil of Egypt^{[1]} 
Muhammad ibn Musa alKhwarizmi^{[note 1]} (Persian: محمد بن موسى خوارزمی; c. 780 – c. 850), or simply alKhwarizmi, was a Khwarazmborn polymath who produced vastly influential Arabiclanguage works in mathematics, astronomy, and geography. Around 820 CE, he was appointed as the astronomer and head of the House of Wisdom in Baghdad, the contemporary capital city of the Abbasid Caliphate.
His popularizing treatise on algebra, compiled between 813–33 as AlJabr (The Compendious Book on Calculation by Completion and Balancing),^{[6]}^{: 171 } presented the first systematic solution of linear and quadratic equations. One of his achievements in algebra was his demonstration of how to solve quadratic equations by completing the square, for which he provided geometric justifications.^{[7]}^{: 14 } Because alKhwarizmi was the first person to treat algebra as an independent discipline and introduced the methods of "reduction" and "balancing" (the transposition of subtracted terms to the other side of an equation, that is, the cancellation of like terms on opposite sides of the equation),^{[8]} he has been described as the father^{[9]}^{[10]}^{[11]} or founder^{[12]}^{[13]} of algebra. The English term algebra comes from the shorthand title of his aforementioned treatise (الجبر AlJabr, transl. "completion" or "rejoining").^{[14]} His name gave rise to the English terms algorism and algorithm; the Spanish, Italian, and Portuguese terms algoritmo; and the Spanish term guarismo^{[15]} and Portuguese term algarismo, both meaning "digit".^{[16]}
In the 12th century, Latinlanguage translations of alKhwarizmi's textbook on Indian arithmetic (Algorithmo de Numero Indorum), which codified the various Indian numerals, introduced the decimalbased positional number system to the Western world.^{[17]} Likewise, AlJabr, translated into Latin by the English scholar Robert of Chester in 1145, was used until the 16th century as the principal mathematical textbook of European universities.^{[18]}^{[19]}^{[20]}^{[21]}
AlKhwarizmi revised Geography, the 2ndcentury Greeklanguage treatise by the Roman polymath Claudius Ptolemy, listing the longitudes and latitudes of cities and localities.^{[22]}^{: 9 } He further produced a set of astronomical tables and wrote about calendric works, as well as the astrolabe and the sundial.^{[23]} AlKhwarizmi made important contributions to trigonometry, producing accurate sine and cosine tables and the first table of tangents.
Life
Few details of alKhwārizmī's life are known with certainty. Ibn alNadim gives his birthplace as Khwarazm, and he is generally thought to have come from this region.^{[24]}^{[25]}^{[26]} Of Persian stock,^{[27]}^{[24]}^{[28]}^{[29]}^{[30]} his name means 'of Khwarazm', a region that was part of Greater Iran,^{[31]} and is now part of Turkmenistan and Uzbekistan.^{[32]}
AlTabari gives his name as Muḥammad ibn Musá alKhwārizmī alMajūsī alQuṭrubbullī (محمد بن موسى الخوارزميّ المجوسـيّ القطربّـليّ). The epithet alQutrubbulli could indicate he might instead have come from Qutrubbul (Qatrabbul),^{[33]} near Baghdad. However, Roshdi Rashed denies this:^{[34]}
There is no need to be an expert on the period or a philologist to see that alTabari's second citation should read "Muhammad ibn Mūsa alKhwārizmī and alMajūsi alQutrubbulli," and that there are two people (alKhwārizmī and alMajūsi alQutrubbulli) between whom the letter wa [Arabic 'و' for the conjunction 'and'] has been omitted in an early copy. This would not be worth mentioning if a series of errors concerning the personality of alKhwārizmī, occasionally even the origins of his knowledge, had not been made. Recently, G.J. Toomer ... with naive confidence constructed an entire fantasy on the error which cannot be denied the merit of amusing the reader.
On the other hand, David A. King affirms his nisba to Qutrubul, noting that he was called alKhwārizmī alQutrubbulli because he was born just outside of Baghdad.^{[35]}
Regarding alKhwārizmī's religion, Toomer writes:^{[36]}
Another epithet given to him by alṬabarī, "alMajūsī," would seem to indicate that he was an adherent of the old Zoroastrian religion. This would still have been possible at that time for a man of Iranian origin, but the pious preface to alKhwārizmī's Algebra shows that he was an orthodox Muslim, so alṬabarī's epithet could mean no more than that his forebears, and perhaps he in his youth, had been Zoroastrians.
Ibn alNadīm's AlFihrist includes a short biography on alKhwārizmī together with a list of his books. AlKhwārizmī accomplished most of his work between 813 and 833. After the Muslim conquest of Persia, Baghdad had become the centre of scientific studies and trade. Around 820 CE, he was appointed as the astronomer and head of the library of the House of Wisdom.^{[7]}^{: 14 } The House of Wisdom was established by the Abbasid Caliph alMa'mūn. AlKhwārizmī studied sciences and mathematics, including the translation of Greek and Sanskrit scientific manuscripts. He was also a historian who is cited by the likes of alTabari and Ibn Abi Tahir.^{[37]}
During the reign of alWathiq, he is said to have been involved in the first of two embassies to the Khazars.^{[38]} Douglas Morton Dunlop suggests that Muḥammad ibn Mūsā alKhwārizmī might have been the same person as Muḥammad ibn Mūsā ibn Shākir, the eldest of the three Banū Mūsā brothers.^{[39]}
Contributions
AlKhwārizmī's contributions to mathematics, geography, astronomy, and cartography established the basis for innovation in algebra and trigonometry. His systematic approach to solving linear and quadratic equations led to algebra, a word derived from the title of his book on the subject, AlJabr.^{[40]}
On the Calculation with Hindu Numerals, written about 820, was principally responsible for spreading the Hindu–Arabic numeral system throughout the Middle East and Europe. It was translated into Latin as Algoritmi de numero Indorum. AlKhwārizmī, rendered in Latin as Algoritmi, led to the term "algorithm".^{[41]}^{[42]}
Some of his work was based on Persian and Babylonian astronomy, Indian numbers, and Greek mathematics.
AlKhwārizmī systematized and corrected Ptolemy's data for Africa and the Middle East. Another major book was Kitab surat alard ("The Image of the Earth"; translated as Geography), presenting the coordinates of places based on those in the Geography of Ptolemy, but with improved values for the Mediterranean Sea, Asia, and Africa.^{[43]}
He wrote on mechanical devices like the astrolabe^{[44]} and sundial.^{[23]} He assisted a project to determine the circumference of the Earth and in making a world map for alMa'mun, the caliph, overseeing 70 geographers.^{[45]} When, in the 12th century, his works spread to Europe through Latin translations, it had a profound impact on the advance of mathematics in Europe.^{[46]}
Algebra
AlJabr (The Compendious Book on Calculation by Completion and Balancing, Arabic: الكتاب المختصر في حساب الجبر والمقابلة alKitāb almukhtaṣar fī ḥisāb aljabr walmuqābala) is a mathematical book written approximately 820 CE. It was written with the encouragement of Caliph alMa'mun as a popular work on calculation and is replete with examples and applications to a range of problems in trade, surveying and legal inheritance.^{[47]} The term "algebra" is derived from the name of one of the basic operations with equations (aljabr, meaning "restoration", referring to adding a number to both sides of the equation to consolidate or cancel terms) described in this book. The book was translated in Latin as Liber algebrae et almucabala by Robert of Chester (Segovia, 1145) hence "algebra", and by Gerard of Cremona. A unique Arabic copy is kept at Oxford and was translated in 1831 by F. Rosen. A Latin translation is kept in Cambridge.^{[48]}
It provided an exhaustive account of solving polynomial equations up to the second degree,^{[49]} and discussed the fundamental method of "reduction" and "balancing", referring to the transposition of terms to the other side of an equation, that is, the cancellation of like terms on opposite sides of the equation.^{[50]}
AlKhwārizmī's method of solving linear and quadratic equations worked by first reducing the equation to one of six standard forms (where b and c are positive integers)
 squares equal roots (ax^{2} = bx)
 squares equal number (ax^{2} = c)
 roots equal number (bx = c)
 squares and roots equal number (ax^{2} + bx = c)
 squares and number equal roots (ax^{2} + c = bx)
 roots and number equal squares (bx + c = ax^{2})
by dividing out the coefficient of the square and using the two operations aljabr (Arabic: الجبر "restoring" or "completion") and almuqābala ("balancing"). Aljabr is the process of removing negative units, roots and squares from the equation by adding the same quantity to each side. For example, x^{2} = 40x − 4x^{2} is reduced to 5x^{2} = 40x. Almuqābala is the process of bringing quantities of the same type to the same side of the equation. For example, x^{2} + 14 = x + 5 is reduced to x^{2} + 9 = x.
The above discussion uses modern mathematical notation for the types of problems that the book discusses. However, in alKhwārizmī's day, most of this notation had not yet been invented, so he had to use ordinary text to present problems and their solutions. For example, for one problem he writes, (from an 1831 translation)
If some one says: "You divide ten into two parts: multiply the one by itself; it will be equal to the other taken eightyone times." Computation: You say, ten less a thing, multiplied by itself, is a hundred plus a square less twenty things, and this is equal to eightyone things. Separate the twenty things from a hundred and a square, and add them to eightyone. It will then be a hundred plus a square, which is equal to a hundred and one roots. Halve the roots; the moiety is fifty and a half. Multiply this by itself, it is two thousand five hundred and fifty and a quarter. Subtract from this one hundred; the remainder is two thousand four hundred and fifty and a quarter. Extract the root from this; it is fortynine and a half. Subtract this from the moiety of the roots, which is fifty and a half. There remains one, and this is one of the two parts.^{[47]}
In modern notation this process, with x the "thing" (شيء shayʾ) or "root", is given by the steps,
Let the roots of the equation be x = p and x = q. Then , and
So a root is given by
Several authors have published texts under the name of Kitāb aljabr walmuqābala, including Abū Ḥanīfa Dīnawarī, Abū Kāmil, Abū Muḥammad al'Adlī, Abū Yūsuf alMiṣṣīṣī, 'Abd alHamīd ibn Turk, Sind ibn 'Alī, Sahl ibn Bišr, and Sharaf alDīn alṬūsī.
Solomon Gandz has described AlKhwarizmi as the father of Algebra:
AlKhwarizmi's algebra is regarded as the foundation and cornerstone of the sciences. In a sense, alKhwarizmi is more entitled to be called "the father of algebra" than Diophantus because alKhwarizmi is the first to teach algebra in an elementary form and for its own sake, Diophantus is primarily concerned with the theory of numbers.^{[51]}
Victor J. Katz adds :
The first true algebra text which is still extant is the work on aljabr and almuqabala by Mohammad ibn Musa alKhwarizmi, written in Baghdad around 825.^{[52]}
John J. O'Connor and Edmund F. Robertson wrote in the MacTutor History of Mathematics Archive:
Perhaps one of the most significant advances made by Arabic mathematics began at this time with the work of alKhwarizmi, namely the beginnings of algebra. It is important to understand just how significant this new idea was. It was a revolutionary move away from the Greek concept of mathematics which was essentially 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, and provided a vehicle for 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.^{[53]}
Roshdi Rashed and Angela Armstrong write:
AlKhwarizmi's text can be seen to be distinct not only from the Babylonian tablets, but also from Diophantus' Arithmetica. It no longer concerns a series of problems to be solved, but an exposition which starts with primitive terms in which the combinations must give all possible prototypes for equations, which henceforward explicitly constitute the true object of study. On the other hand, the idea of an equation for its own sake appears from the beginning and, one could say, in a generic manner, insofar as it does not simply emerge in the course of solving a problem, but is specifically called on to define an infinite class of problems.^{[54]}
According to SwissAmerican historian of mathematics, Florian Cajori, AlKhwarizmi's algebra was different from the work of Indian mathematicians, for Indians had no rules like the restoration and reduction.^{[55]} Regarding the dissimilarity and significance of AlKhwarizmi's algebraic work from that of Indian Mathematician Brahmagupta, Carl B. Boyer wrote:
It is true that in two respects the work of alKhowarizmi represented a retrogression from that of Diophantus. First, it is on a far more elementary level than that found in the Diophantine problems and, second, the algebra of alKhowarizmi is thoroughly rhetorical, with none of the syncopation found in the Greek Arithmetica or in Brahmagupta's work. Even numbers were written out in words rather than symbols! It is quite unlikely that alKhwarizmi knew of the work of Diophantus, but he must have been familiar with at least the astronomical and computational portions of Brahmagupta; yet neither alKhwarizmi nor other Arabic scholars made use of syncopation or of negative numbers. Nevertheless, the Aljabr comes closer to the elementary algebra of today than the works of either Diophantus or Brahmagupta, because the book is not concerned with difficult problems in indeterminant analysis but with a straight forward and elementary exposition of the solution of equations, especially that of second degree. The Arabs in general loved a good clear argument from premise to conclusion, as well as systematic organization – respects in which neither Diophantus nor the Hindus excelled.^{[56]}
Arithmetic
AlKhwārizmī's second most influential work was on the subject of arithmetic, which survived in Latin translations but is lost in the original Arabic. His writings include the text kitāb alḥisāb alhindī ('Book of Indian computation'^{[note 2]}), and perhaps a more elementary text, kitab aljam' wa'ltafriq alḥisāb alhindī ('Addition and subtraction in Indian arithmetic').^{[58]}^{[59]} These texts described algorithms on decimal numbers (Hindu–Arabic numerals) that could be carried out on a dust board. Called takht in Arabic (Latin: tabula), a board covered with a thin layer of dust or sand was employed for calculations, on which figures could be written with a stylus and easily erased and replaced when necessary. AlKhwarizmi's algorithms were used for almost three centuries, until replaced by AlUqlidisi's algorithms that could be carried out with pen and paper.^{[60]}
As part of 12th century wave of Arabic science flowing into Europe via translations, these texts proved to be revolutionary in Europe.^{[61]} AlKhwarizmi's Latinized name, Algorismus, turned into the name of method used for computations, and survives in the term "algorithm". It gradually replaced the previous abacusbased methods used in Europe.^{[62]}
Four Latin texts providing adaptions of AlKhwarizmi's methods have survived, even though none of them is believed to be a literal translation:^{[58]}
 Dixit Algorizmi (published in 1857 under the title Algoritmi de Numero Indorum^{[63]})^{[64]}
 Liber Alchoarismi de Practica Arismetice
 Liber Ysagogarum Alchorismi
 Liber Pulveris
Dixit Algorizmi ('Thus spake AlKhwarizmi') is the starting phrase of a manuscript in the University of Cambridge library, which is generally referred to by its 1857 title Algoritmi de Numero Indorum. It is attributed to the Adelard of Bath, who had translated the astronomical tables in 1126. It is perhaps the closest to AlKhwarizmi's own writings.^{[64]}
AlKhwarizmi's work on arithmetic was responsible for introducing the Arabic numerals, based on the Hindu–Arabic numeral system developed in Indian mathematics, to the Western world. The term "algorithm" is derived from the algorism, the technique of performing arithmetic with HinduArabic numerals developed by alKhwārizmī. Both "algorithm" and "algorism" are derived from the Latinized forms of alKhwārizmī's name, Algoritmi and Algorismi, respectively.^{[65]}
Astronomy
AlKhwārizmī's Zīj asSindhind^{[36]} (Arabic: زيج السند هند, "astronomical tables of Siddhanta"^{[66]}) is a work consisting of approximately 37 chapters on calendrical and astronomical calculations and 116 tables with calendrical, astronomical and astrological data, as well as a table of sine values. This is the first of many Arabic Zijes based on the Indian astronomical methods known as the sindhind.^{[67]} The word Sindhind is a corruption of the Sanskrit Siddhānta, which is the usual designation of an astronomical textbook. In fact, the mean motions in the tables of alKhwarizmi are derived from those in the "corrected Brahmasiddhanta" (Brahmasphutasiddhanta) of Brahmagupta.^{[68]}
The work contains tables for the movements of the sun, the moon and the five planets known at the time. This work marked the turning point in Islamic astronomy. Hitherto, Muslim astronomers had adopted a primarily research approach to the field, translating works of others and learning already discovered knowledge.
The original Arabic version (written c. 820) is lost, but a version by the Spanish astronomer Maslama alMajriti (c. 1000) has survived in a Latin translation, presumably by Adelard of Bath (26 January 1126).^{[69]} The four surviving manuscripts of the Latin translation are kept at the Bibliothèque publique (Chartres), the Bibliothèque Mazarine (Paris), the Biblioteca Nacional (Madrid) and the Bodleian Library (Oxford).
Trigonometry
AlKhwārizmī's Zīj asSindhind contained tables for the trigonometric functions of sines and cosine.^{[67]} A related treatise on spherical trigonometry is attributed to him.^{[53]}
AlKhwārizmī produced accurate sine and cosine tables, and the first table of tangents.^{[70]}^{[71]}
Geography
AlKhwārizmī's third major work is his Kitāb Ṣūrat alArḍ (Arabic: كتاب صورة الأرض, "Book of the Description of the Earth"),^{[72]} also known as his Geography, which was finished in 833. It is a major reworking of Ptolemy's secondcentury Geography, consisting of a list of 2402 coordinates of cities and other geographical features following a general introduction.^{[73]}
There is one surviving copy of Kitāb Ṣūrat alArḍ, which is kept at the Strasbourg University Library.^{[74]}^{[75]} A Latin translation is at the Biblioteca Nacional de España in Madrid.^{[76]} The book opens with the list of latitudes and longitudes, in order of "weather zones", that is to say in blocks of latitudes and, in each weather zone, by order of longitude. As Paul Gallez notes, this system allows the deduction of many latitudes and longitudes where the only extant document is in such a bad condition, as to make it practically illegible. Neither the Arabic copy nor the Latin translation include the map of the world; however, Hubert Daunicht was able to reconstruct the missing map from the list of coordinates. Daunicht read the latitudes and longitudes of the coastal points in the manuscript, or deduced them from the context where they were not legible. He transferred the points onto graph paper and connected them with straight lines, obtaining an approximation of the coastline as it was on the original map. He did the same for the rivers and towns.^{[77]}
AlKhwārizmī corrected Ptolemy's gross overestimate for the length of the Mediterranean Sea^{[78]} from the Canary Islands to the eastern shores of the Mediterranean; Ptolemy overestimated it at 63 degrees of longitude, while alKhwārizmī almost correctly estimated it at nearly 50 degrees of longitude. He "depicted the Atlantic and Indian Oceans as open bodies of water, not landlocked seas as Ptolemy had done."^{[79]} AlKhwārizmī's Prime Meridian at the Fortunate Isles was thus around 10° east of the line used by Marinus and Ptolemy. Most medieval Muslim gazetteers continued to use alKhwārizmī's prime meridian.^{[78]}
Jewish calendar
AlKhwārizmī wrote several other works including a treatise on the Hebrew calendar, titled Risāla fi istikhrāj ta'rīkh alyahūd (Arabic: رسالة في إستخراج تأريخ اليهود, "Extraction of the Jewish Era"). It describes the Metonic cycle, a 19year intercalation cycle; the rules for determining on what day of the week the first day of the month Tishrei shall fall; calculates the interval between the Anno Mundi or Jewish year and the Seleucid era; and gives rules for determining the mean longitude of the sun and the moon using the Hebrew calendar. Similar material is found in the works of AlBīrūnī and Maimonides.^{[36]}
Other works
Ibn alNadim's AlFihrist, an index of Arabic books, mentions alKhwārizmī's Kitāb alTaʾrīkh (Arabic: كتاب التأريخ), a book of annals. No direct manuscript survives; however, a copy had reached Nusaybin by the 11th century, where its metropolitan bishop, Mar Elias bar Shinaya, found it. Elias's chronicle quotes it from "the death of the Prophet" through to 169 AH, at which point Elias's text itself hits a lacuna.^{[80]}
Several Arabic manuscripts in Berlin, Istanbul, Tashkent, Cairo and Paris contain further material that surely or with some probability comes from alKhwārizmī. The Istanbul manuscript contains a paper on sundials; the Fihrist credits alKhwārizmī with Kitāb arRukhāma(t) (Arabic: كتاب الرخامة). Other papers, such as one on the determination of the direction of Mecca, are on the spherical astronomy.
Two texts deserve special interest on the morning width (Ma'rifat sa'at almashriq fī kull balad) and the determination of the azimuth from a height (Ma'rifat alsamt min qibal alirtifā'). He wrote two books on using and constructing astrolabes.
Honours
 AlKhwarizmi (crater) — A crater on the far side of the Moon. ^{[81]}
 13498 Al Chwarizmi — Mainbelt Asteroid, Discovered 1986 Aug 6 by E. W. Elst and V. G. Ivanova at Smolyan.^{[82]}
 11156 AlKhwarismi — Mainbelt Asteroid, Discovered 1997 Dec 31 by P. G. Comba at Prescott.^{[83]}
Notes
 ^ There is some confusion in the literature on whether alKhwārizmī's full name is ابو عبدالله محمد بن موسى خوارزمی Abū ʿAbdallāh Muḥammad ibn Mūsā alKhwārizmī or ابوجعفر محمد بن موسی خوارزمی Abū Ja'far Muḥammad ibn Mūsā alKhwārizmī. Ibn Khaldun notes in his Prolegomena: "The first to write on this discipline [algebra] was Abu 'Abdallah alKhuwarizmi. After him, there was Abu Kamil Shuja' b. Aslam. People followed in his steps."^{[4]} In the introduction to his critical commentary on Robert of Chester's Latin translation of alKhwārizmī's Algebra, L.C. Karpinski notes that Abū Ja'far Muḥammad ibn Mūsā refers to the eldest of the Banū Mūsā brothers. Karpinski notes in his review on (Ruska 1917) that in (Ruska 1918): "Ruska here inadvertently speaks of the author as Abū Ga'far M. b. M., instead of Abū Abdallah M. b. M." Donald Knuth writes it as Abū 'Abd Allāh Muḥammad ibn Mūsā alKhwārizmī and quotes it as meaning "literally, 'Father of Abdullah, Mohammed, son of Moses, native of Khwārizm,'" citing previous work by Heinz Zemanek.^{[5]}
 ^ Some scholars translate the title alḥisāb alhindī as "computation with Hindu numerals", but Arabic Hindī means 'Indian' rather than 'Hindu'. A. S. Saidan states that it should be understood as arithmetic done "in the Indian way", with HinduArabic numerals, rather than as simply "Indian arithmetic". The Arab mathematicians incorporated their own innovations in their texts.^{[57]}
References
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 ^ Toomer, Gerald J. (1970–1980). "alKhuwārizmī, Abu Ja'far Muḥammad ibn Mūsā". In Gillispie, Charles Coulston (ed.). Dictionary of Scientific Biography. Vol. VII. pp. 358–365. ISBN 9780684169668.
 ^ Vernet, Juan (1960–2005). "AlKhwārizmī". In Gibb, H. A. R.; Kramers, J. H.; LéviProvençal, E.; Schacht, J. (eds.). The Encyclopaedia of Islam. Vol. IV (2nd ed.). Leiden: Brill. pp. 1070–1071. OCLC 399624.
 ^ Ibn Khaldūn, The Muqaddimah: An introduction to history Archived 17 September 2016 at the Wayback Machine, Translated from the Arabic by Franz Rosenthal, New York: Princeton (1958), Chapter VI:19.
 ^ Knuth, Donald (1997). "Basic Concepts". The Art of Computer Programming. Vol. 1 (3rd ed.). AddisonWesley. p. 1. ISBN 9780201896831.
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 ^ ^{a} ^{b} Maher, P. (1998), "From AlJabr to Algebra", Mathematics in School, 27(4), 14–15.
 ^ (Boyer 1991, "The Arabic Hegemony" p. 229) "It is not certain just what the terms aljabr and muqabalah mean, but the usual interpretation is similar to that implied in the translation above. The word aljabr presumably meant something like "restoration" or "completion" and seems to refer to the transposition of subtracted terms to the other side of an equation; the word muqabalah is said to refer to "reduction" or "balancing" – that is, the cancellation of like terms on opposite sides of the equation."
 ^ Corbin, Henry (1998). The Voyage and the Messenger: Iran and Philosophy. North Atlantic Books. p. 44. ISBN 9781556432699. Archived from the original on 28 March 2023. Retrieved 19 October 2020.
 ^ Boyer, Carl B., 1985. A History of Mathematics, p. 252. Princeton University Press. "Diophantus sometimes is called the father of algebra, but this title more appropriately belongs to alKhowarizmi...", "...the Aljabr comes closer to the elementary algebra of today than the works of either Diophantus or Brahmagupta..."
 ^ Gandz, Solomon, The sources of alKhwarizmi's algebra, Osiris, i (1936), 263–277, "AlKhwarizmi's algebra is regarded as the foundation and cornerstone of the sciences. In a sense, alKhwarizmi is more entitled to be called "the father of algebra" than Diophantus because alKhwarizmi is the first to teach algebra in an elementary form and for its own sake, Diophantus is primarily concerned with the theory of numbers."
 ^ Katz, Victor J. "Stages in the History of Algebra with Implications for Teaching" (PDF). VICTOR J.KATZ, University of the District of Columbia Washington DC, USA: 190. Archived from the original (PDF) on 27 March 2019. Retrieved 7 October 2017 – via University of the District of Columbia Washington DC, USA.
The first true algebra text which is still extant is the work on aljabr and almuqabala by Mohammad ibn Musa alKhwarizmi, written in Baghdad around 825.
 ^ Esposito, John L. (6 April 2000). The Oxford History of Islam. Oxford University Press. p. 188. ISBN 9780199880416. Archived from the original on 28 March 2023. Retrieved 29 September 2020.
AlKhwarizmi is often considered the founder of algebra, and his name gave rise to the term algorithm.
 ^ Brentjes, Sonja (1 June 2007). "Algebra". Encyclopaedia of Islam, THREE. Archived from the original on 22 December 2019. Retrieved 5 June 2019.
 ^ Knuth, Donald (1979). Algorithms in Modern Mathematics and Computer Science (PDF). SpringerVerlag. ISBN 9780387111575. Archived from the original (PDF) on 7 November 2006.
 ^ Gandz, Solomon (1926). "The Origin of the Term "Algebra"". The American Mathematical Monthly. 33 (9): 437–440. doi:10.2307/2299605. ISSN 00029890. JSTOR 2299605.
 ^ Struik 1987, p. 93
 ^ Philip Khuri Hitti (2002). History of the Arabs. Palgrave Macmillan. p. 379. ISBN 9781137039828. Archived from the original on 20 December 2019.
 ^ Fred James Hill, Nicholas Awde (2003). A History of the Islamic World. Hippocrene Books. p. 55. ISBN 9780781810159.
"The Compendious Book on Calculation by Completion and Balancing" (Hisab alJabr wa HMuqabala) on the development of the subject cannot be underestimated. Translated into Latin during the twelfth century, it remained the principal mathematics textbook in European universities until the sixteenth century
 ^ Shawn Overbay; Jimmy Schorer; Heather Conger. "AlKhwarizmi". University of Kentucky. Archived from the original on 12 December 2013.
 ^ "Islam Spain and the history of technology". www.sjsu.edu. Archived from the original on 11 October 2018. Retrieved 24 January 2018.
 ^ van der Waerden, Bartel Leendert (1985). A History of Algebra: From al–Khwarizmi to Emmy Noether. Berlin: SpringerVerlag.
 ^ ^{a} ^{b} Arndt 1983, p. 669
 ^ ^{a} ^{b} Saliba, George (September 1998). "Science and medicine". Iranian Studies. 31 (3–4): 681–690. doi:10.1080/00210869808701940.
Take, for example, someone like Muhammad b. Musa alKhwarizmi (fl. 850) may present a problem for the EIr, for although he was obviously of Persian descent, he lived and worked in Baghdad and was not known to have produced a single scientific work in Persian.
 ^ Oaks, Jeffrey A. (2014). "Khwārizmī". In Kalin, Ibrahim (ed.). The Oxford Encyclopedia of Philosophy, Science, and Technology in Islam. Vol. 1. Oxford: Oxford University Press. pp. 451–459. ISBN 9780199812578. Archived from the original on 30 January 2022. Retrieved 6 September 2021.
"Ibn alNadīm and Ibn alQifṭī relate that alKhwārizmī's family came from Khwārizm, the region south of the Aral sea."
Also → alNadīm, Abu'lFaraj (1871–1872). Kitāb alFihrist, ed. Gustav Flügel, Leipzig: Vogel, p. 274. alQifṭī, Jamāl alDīn (1903). Taʾrīkh alHukamā, eds. August Müller & Julius Lippert, Leipzig: Theodor Weicher, p. 286.  ^ Dodge, Bayard, ed. (1970), The Fihrist of alNadīm: A TenthCentury Survey of Islamic Culture, vol. 2, translated by Dodge, New York: Columbia University Press
 ^ Clifford A. Pickover (2009). The Math Book: From Pythagoras to the 57th Dimension, 250 Milestones in the History of Mathematics. Sterling Publishing Company, Inc. p. 84. ISBN 9781402757969. Archived from the original on 28 March 2023. Retrieved 19 October 2020.
 ^ A History of Science in World Cultures: Voices of Knowledge. Routledge. Page 228. "Mohammed ibn Musa alKhwarizmi (780–850) was a Persian astronomer and mathematician from the district of Khwarism (Uzbekistan area of Central Asia)."
 ^ BenMenahem, Ari (2009). Historical Encyclopedia of Natural and Mathematical Sciences (1st ed.). Berlin: Springer. pp. 942–943. ISBN 9783540688310.
Persian mathematician AlKhowarizmi
 ^ WiesnerHanks, Merry E.; Ebrey, Patricia Buckley; Beck, Roger B.; Davila, Jerry; Crowston, Clare Haru; McKay, John P. (2017). A History of World Societies (11th ed.). Bedford/St. Martin's. p. 419.
Near the beginning of this period the Persian scholar alKhwarizmi (d. ca. 850) harmonized Greek and Indian findings to produce astronomical tables that formed the basis for later Eastern and Western research.
 ^ Encycloaedia Iranicaonline, s.v. "CHORASMIA, ii. In Islamic times Archived 2 September 2021 at the Wayback Machine," by Clifford E. Bosworth.
 ^ Bosworth, Clifford Edmund (1960–2005). "Khwārazm". In Gibb, H. A. R.; Kramers, J. H.; LéviProvençal, E.; Schacht, J. (eds.). The Encyclopaedia of Islam. Vol. IV (2nd ed.). Leiden: Brill. pp. 1060–1065. OCLC 399624.
 ^ "Iraq After the Muslim Conquest", by Michael G. Morony, ISBN 1593333153 (a 2005 facsimile from the original 1984 book), p. 145 Archived 27 June 2014 at the Wayback Machine
 ^ Rashed, Roshdi (1988). "alKhwārizmī's Concept of Algebra". In Zurayq, Qusṭanṭīn; Atiyeh, George Nicholas; Oweiss, Ibrahim M. (eds.). Arab Civilization: Challenges and Responses : Studies in Honor of Constantine K. Zurayk. SUNY Press. p. 108. ISBN 9780887066986. Archived from the original on 28 March 2023. Retrieved 19 October 2015.
 ^ King, David A. (7 March 2018). Astronomy in the Service of Islam. AlFurqān Islamic Heritage Foundation – Centre for the Study of Islamic Manuscripts. Event occurs at 20:51. Archived from the original on 1 December 2021. Retrieved 26 November 2021.
I mention another name of Khwarizmi to show that he didn't come from Central Asia. He came from Qutrubul, just outside Baghdad. He was born there, otherwise he wouldn't be called alQutrubulli. Many people say he came from Khwarazm, tsktsk.
 ^ ^{a} ^{b} ^{c} Toomer 1990
 ^ Bosworth, C. E., ed. (1987). The History of alṬabarī, Volume XXXII: The Reunification of the ʿAbbāsid Caliphate: The Caliphate of alMaʾmūn, A.D. 813–33/A.H. 198–213. SUNY Series in Near Eastern Studies. Albany, New York: State University of New York Press. p. 158. ISBN 9780887060588.
 ^ Golden, Peter; BenShammai, Haggai; RonáTas, András (13 August 2007). The World of the Khazars: New Perspectives. Selected Papers from the Jerusalem 1999 International Khazar Colloquium. BRILL. p. 376. ISBN 9789047421450.
 ^ Dunlop 1943
 ^ Yahya Tabesh; Shima Salehi. "Mathematics Education in Iran From Ancient to Modern" (PDF). Sharif University of Technology. Archived (PDF) from the original on 16 April 2018. Retrieved 16 April 2018.
 ^ Daffa 1977
 ^ Clegg, Brian (1 October 2019). Scientifica Historica: How the world's great science books chart the history of knowledge. Ivy Press. p. 61. ISBN 9781782408796. Archived from the original on 28 March 2023. Retrieved 30 December 2021.
 ^ Edu, World History (28 September 2022). "AlKhwārizmī  Biography, Notable Achievements & Facts".
 ^ Joseph Frank, alKhwarizmi über das Astrolab, 1922.
 ^ "alKhwarizmi". Encyclopædia Britannica. Archived from the original on 5 January 2008. Retrieved 30 May 2008.
 ^ "AlKhwarizmi  Biography & Facts  Britannica". www.britannica.com. 1 December 2023.
 ^ ^{a} ^{b} Rosen, Frederic. "The Compendious Book on Calculation by Completion and Balancing, alKhwārizmī". 1831 English Translation. Archived from the original on 16 July 2011. Retrieved 14 September 2009.
 ^ Karpinski, L.C. (1912). "History of Mathematics in the Recent Edition of the Encyclopædia Britannica". Science. 35 (888): 29–31. Bibcode:1912Sci....35...29K. doi:10.1126/science.35.888.29. PMID 17752897. Archived from the original on 30 October 2020. Retrieved 29 September 2020.
 ^ Boyer 1991, p. 228: "The Arabs in general loved a good clear argument from premise to conclusion, as well as systematic organization — respects in which neither Diophantus nor the Hindus excelled."
 ^ (Boyer 1991, "The Arabic Hegemony" p. 229) "It is not certain just what the terms aljabr and muqabalah mean, but the usual interpretation is similar to that implied in the translation above. The word aljabr presumably meant something like "restoration" or "completion" and seems to refer to the transposition of subtracted terms to the other side of an equation; the word muqabalah is said to refer to "reduction" or "balancing" — that is, the cancellation of like terms on opposite sides of the equation."
 ^ Gandz, Solomon, The sources of alKhwarizmi's algebra, Osiris, i (1936), 263–277
 ^ Katz, Victor J. "Stages in the History of Algebra with Implications for Teaching" (PDF). VICTOR J.KATZ, University of the District of Columbia Washington DC, USA: 190. Archived from the original (PDF) on 27 March 2019. Retrieved 7 October 2017 – via University of the District of Columbia Washington DC, USA.
 ^ ^{a} ^{b} O'Connor, John J.; Robertson, Edmund F., "Abu Ja'far Muhammad ibn Musa AlKhwarizmi", MacTutor History of Mathematics Archive, University of St Andrews
 ^ Rashed, R.; Armstrong, Angela (1994). The Development of Arabic Mathematics. Springer. pp. 11–12. ISBN 9780792325659. OCLC 29181926.
 ^ Florian Cajori (1919). A History of Mathematics. Macmillan. p. 103.
That it came from Indian source is impossible, for Hindus had no rules like "restoration" and "reduction". They were never in the habit of making all terms in an equation positive, as is done in the process of "restoration.
 ^ Boyer, Carl Benjamin (1968). A History of Mathematics. p. 252.
 ^ Saidan, A. S. (Winter 1966), "The Earliest Extant Arabic Arithmetic: Kitab alFusul fi al Hisab alHindi of Abu alHasan, Ahmad ibn Ibrahim alUqlidisi", Isis, 57 (4), The University of Chicago Press: 475–490, doi:10.1086/350163, JSTOR 228518, S2CID 143979243
 ^ ^{a} ^{b} Burnett 2017, p. 39.
 ^ Avari, Burjor (2013), Islamic Civilization in South Asia: A history of Muslim power and presence in the Indian subcontinent, Routledge, pp. 31–32, ISBN 9780415580618, archived from the original on 28 March 2023, retrieved 29 September 2020
 ^ Van Brummelen, Glen (2017), "Arithmetic", in Thomas F. Glick (ed.), Routledge Revivals: Medieval Science, Technology and Medicine (2006): An Encyclopedia, Taylor & Francis, p. 46, ISBN 9781351676175, archived from the original on 28 March 2023, retrieved 5 May 2019
 ^ Thomas F. Glick, ed. (2017), "AlKhwarizmi", Routledge Revivals: Medieval Science, Technology and Medicine (2006): An Encyclopedia, Taylor & Francis, ISBN 9781351676175, archived from the original on 28 March 2023, retrieved 6 May 2019
 ^ Van Brummelen, Glen (2017), "Arithmetic", in Thomas F. Glick (ed.), Routledge Revivals: Medieval Science, Technology and Medicine (2006): An Encyclopedia, Taylor & Francis, pp. 46–47, ISBN 9781351676175, archived from the original on 28 March 2023, retrieved 5 May 2019
 ^ "Algoritmi de numero Indorum", Trattati D'Aritmetica, Rome: Tipografia delle Scienze Fisiche e Matematiche, 1857, pp. 1–, archived from the original on 28 March 2023, retrieved 6 May 2019
 ^ ^{a} ^{b} Crossley, John N.; Henry, Alan S. (1990), "Thus Spake alKhwārizmī: A Translation of the Text of Cambridge University Library Ms. Ii.vi.5", Historia Mathematica, 17 (2): 103–131, doi:10.1016/03150860(90)90048I
 ^ "How Algorithm Got Its Name". earthobservatory.nasa.gov. 8 January 2018.
 ^ Thurston, Hugh (1996), Early Astronomy, Springer Science & Business Media, pp. 204–, ISBN 9780387948225
 ^ ^{a} ^{b} Kennedy 1956, pp. 26–29
 ^ van der Waerden, Bartel Leendert (1985). A History of Algebra: From alKhwārizmī to Emmy Noether. Berlin Heidelberg: SpringerVerlag. p. 10. ISBN 9783642516016. Archived from the original on 24 June 2021. Retrieved 22 June 2021.
 ^ Kennedy 1956, p. 128
 ^ Jacques Sesiano, "Islamic mathematics", p. 157, in Selin, Helaine; D'Ambrosio, Ubiratan, eds. (2000). Mathematics Across Cultures: The History of Nonwestern Mathematics. Springer Science+Business Media. ISBN 9781402002601.
 ^ "trigonometry". Encyclopædia Britannica. Archived from the original on 6 July 2008. Retrieved 21 July 2008.
 ^ The full title is "The Book of the Description of the Earth, with its Cities, Mountains, Seas, All the Islands and the Rivers, written by Abu Ja'far Muhammad ibn Musa alKhwārizmī, according to the Geographical Treatise written by Ptolemy the Claudian", although due to ambiguity in the word surah it could also be understood as meaning "The Book of the Image of the Earth" or even "The Book of the Map of the World".
 ^ "The history of cartography". GAP computer algebra system. Archived from the original on 24 May 2008. Retrieved 30 May 2008.
 ^ "Consultation". archivesetmanuscrits.bnf.fr. Retrieved 27 August 2024.
 ^ alḪwarizmī, Muḥammad Ibn Mūsā (1926). Das Kitāb ṣūrat alarḍ des Abū Ǧaʻfar Muḥammad Ibn Mūsā alḪuwārizmī (in Arabic).
 ^ Keith J. Devlin (2012). The Man of Numbers: Fibonacci's Arithmetic Revolution (Paperback). Bloomsbury. p. 55. ISBN 9781408822487.
 ^ Daunicht
 ^ ^{a} ^{b} Edward S. Kennedy, Mathematical Geography, p. 188, in (Rashed & Morelon 1996, pp. 185–201)
 ^ Covington, Richard (2007). "The Third Dimension". Saudi Aramco World, May–June 2007: 17–21. Archived from the original on 12 May 2008. Retrieved 6 July 2008.
 ^ LJ Delaporte (1910). Chronographie de Mar Elie bar Sinaya. p. xiii.
 ^ ElBaz, Farouk (1973). "AlKhwarizmi: A NewFound Basin on the Lunar Far Side". Science. 180 (4091): 1173–1176. Bibcode:1973Sci...180.1173E. doi:10.1126/science.180.4091.1173. JSTOR 1736378. PMID 17743602. S2CID 10623582. NASA Portal: Apollo 11, Photography Index.
 ^ "SmallBody Database Lookup". ssd.jpl.nasa.gov.
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Sources
 Arndt, A. B. (December 1983). "AlKhwarizmi". The Mathematics Teacher. 76 (9): 668–670. doi:10.5951/MT.76.9.0668. JSTOR 27963784.
 Boyer, Carl B. (1991). "The Arabic Hegemony". A History of Mathematics (Second ed.). John Wiley & Sons, Inc. ISBN 9780471543978.
 Burnett, Charles (2017), "Arabic Numerals", in Thomas F. Glick (ed.), Routledge Revivals: Medieval Science, Technology and Medicine (2006): An Encyclopedia, Taylor & Francis, ISBN 9781351676175, archived from the original on 28 March 2023, retrieved 5 May 2019
 Daffa, Ali Abdullah al (1977). The Muslim contribution to mathematics. London: Croom Helm. ISBN 9780856644641.
 Dunlop, Douglas Morton (1943). "Muḥammad b. Mūsā alKhwārizmī". The Journal of the Royal Asiatic Society of Great Britain and Ireland. 2 (3–4): 248–250. doi:10.1017/S0035869X00098464. JSTOR 25221920. S2CID 161841351. Archived from the original on 25 June 2021. Retrieved 24 June 2021.
 Kennedy, E. S. (1956). "A Survey of Islamic Astronomical Tables". Transactions of the American Philosophical Society. 46 (2): 123–177. doi:10.2307/1005726. hdl:2027/mdp.39076006359272. JSTOR 1005726. Archived from the original on 4 June 2021. Retrieved 24 June 2021.
 Rashed, Roshdi; Morelon, Régis (1996), Encyclopedia of the History of Arabic Science, vol. 1, Routledge, ISBN 0415124107
 Struik, Dirk Jan (1987). A Concise History of Mathematics (4th ed.). Dover Publications. ISBN 9780486602554.
 Toomer, Gerald (1990). "AlKhwārizmī, Abu Ja'far Muḥammad ibn Mūsā". In Gillispie, Charles Coulston (ed.). Dictionary of Scientific Biography. Vol. 7. New York: Charles Scribner's Sons. ISBN 9780684169620. Archived from the original on 2 July 2016. Retrieved 31 December 2010.
Further reading
Biographical
 Brentjes, Sonja (2007). "Khwārizmī: Muḥammad ibn Mūsā alKhwārizmī Archived 6 July 2011 at the Wayback Machine" in Thomas Hockey et al.(eds.). The Biographical Encyclopedia of Astronomers, Springer Reference. New York: Springer, 2007, pp. 631–633. (PDF version Archived 14 January 2012 at the Wayback Machine)
 Hogendijk, Jan P., Muhammad ibn Musa (Al)Khwarizmi (c. 780–850 CE) Archived 3 February 2018 at the Wayback Machine – bibliography of his works, manuscripts, editions and translations.
 O'Connor, John J.; Robertson, Edmund F., "Abu Ja'far Muhammad ibn Musa AlKhwarizmi", MacTutor History of Mathematics Archive, University of St Andrews
 Sezgin, F., ed., Islamic Mathematics and Astronomy, Frankfurt: Institut für Geschichte der arabischislamischen Wissenschaften, 1997–99.
Algebra
 Gandz, Solomon (November 1926). "The Origin of the Term "Algebra". The American Mathematical Monthly. 33 (9): 437–440. doi:10.2307/2299605. JSTOR 2299605. Archived from the original on 25 June 2021. Retrieved 24 June 2021.
 Gandz, Solomon (1936). "The Sources of alKhowārizmī's Algebra". Osiris. 1 (1): 263–277. doi:10.1086/368426. JSTOR 301610. S2CID 60770737. Archived from the original on 25 June 2021. Retrieved 24 June 2021.
 Gandz, Solomon (1938). "The Algebra of Inheritance: A Rehabilitation of AlKhuwārizmī". Osiris. 5 (5): 319–391. doi:10.1086/368492. JSTOR 301569. S2CID 143683763. Archived from the original on 25 June 2021. Retrieved 24 June 2021.
 Hughes, Barnabas (1986). "Gerard of Cremona's Translation of alKhwārizmī's alJabr, A Critical Edition". Mediaeval Studies. 48: 211–263. doi:10.1484/J.MS.2.306339.
 Hughes, Barnabas. Robert of Chester's Latin translation of alKhwarizmi's alJabr: A new critical edition. In Latin. F. Steiner Verlag Wiesbaden (1989). ISBN 3515045899.
 Karpinski, L.C. (1915). Robert of Chester's Latin Translation of the Algebra of AlKhowarizmi: With an Introduction, Critical Notes and an English Version. The Macmillan Company. Archived from the original on 24 September 2020. Retrieved 21 May 2020.
 Rosen, Fredrick (1831). The Algebra of Mohammed Ben Musa. London.
Astronomy
 Goldstein, B.R. (1968). Commentary on the Astronomical Tables of AlKhwarizmi: By Ibn AlMuthanna. Yale University Press. ISBN 9780300004984.
 Hogendijk, Jan P. (1991). "AlKhwārizmī's Table of the "Sine of the Hours" and the Underlying Sine Table". Historia Scientiarum. 42: 1–12. Archived from the original on 7 May 2021. Retrieved 24 June 2021. (Hogendijk's homepage. Publication in English, no. 25).
 King, David A. (1983). AlKhwārizmī and New Trends in Mathematical Astronomy in the Ninth Century. New York University: Hagop Kevorkian Center for Near Eastern Studies: Occasional Papers on the Near East 2. Archived from the original on 25 June 2021. Retrieved 24 June 2021. (Description and analysis of seven recently discovered minor works related to alKhwarizmi).
 Neugebauer, Otto (1962). The Astronomical Tables of alKhwarizmi.
 Rosenfeld, Boris A. (1993). "'Geometric trigonometry' in treatises of alKhwārizmī, alMāhānī and Ibn alHaytham". In Folkerts, Menso; Hogendijk, Jan P. (eds.). Vestigia Mathematica: Studies in Medieval and Early Modern Mathematics in Honour of H.L.L. Busard. Leiden: Brill. pp. 305–308. ISBN 9789051835366.
 Van Dalen, Benno (1996). "alKhwârizmî's Astronomical Tables Revisited: Analysis of the Equation of Time". In Casulleras, Josep; Samsó, Julio (eds.). From Baghdad to Barcelona, Studies on the Islamic Exact Sciences in Honour of Prof. Juan Vernet. Barcelona: Instituto Millás Vallicrosa de Historia de la Ciencia Arabe. pp. 195–252. Archived from the original on 24 June 2021. Retrieved 24 June 2021. (Van Dalen's homepage. List of Publications, Articles – no. 5).
Jewish calendar
 Kennedy, E. S. (1964). "AlKhwārizmī on the Jewish Calendar". Scripta Mathematica. 27: 55–59.
External links
 Media related to Muhammad ibn Musa alKhwarizmi at Wikimedia Commons
 Earliest Manuscript of Kitab Surat alArd in the Strasbourg National Library
 780s births
 850 deaths
 8thcentury Arabiclanguage writers
 8thcentury astrologers
 8thcentury Iranian astronomers
 8thcentury people from the Abbasid Caliphate
 9thcentury Arabiclanguage writers
 9thcentury astrologers
 9thcentury cartographers
 9thcentury geographers
 9thcentury inventors
 9thcentury Iranian astronomers
 9thcentury people from the Abbasid Caliphate
 9thcentury Iranian mathematicians
 Astronomers from the Abbasid Caliphate
 Astronomers of the medieval Islamic world
 Geographers from the Abbasid Caliphate
 Inventors of the medieval Islamic world
 Mathematicians from the Abbasid Caliphate
 Mathematicians who worked on Islamic inheritance
 Medieval Iranian astrologers
 Medieval Iranian geographers
 People from Khwarazm
 People from Xorazm Region
 Transoxanian Islamic scholars
 Persian physicists
 Scientists who worked on qibla determination
 Writers about religion and science