Abu Ja’far Muhammad Ibn Musa al-Khawarizmi

Circa 780-circa 850

Mathematician

Sources

Algebra . An Arab, Abu Ja’far Muhammad ibn Musa al-Khawarizmi spent most of his life in Baghdad. He served on the faculty at the famous Dar al-Hikma (House of Wisdom), where he not only translated scientific and mathematical documents from Greek, Sanskrit, and Hebrew into Arabic but also taught mathematics and astronomy. His most important known work was the Kitab al-jabr wa al-muqabalah (Large Book on Calculation by Completion and Balancing, circa 833), the earliest compendium of algebra and geometry in Arabic. His compiling of all known algebraic, geometric, and numeral resources into one volume in Arabic created the first textbook containing practical ways to make calculations for construction, surveying, and the complex system of Islamic distribution of family inheritance. The catalyst for popularizing al-jabr (algebra, meaning “completion” in Arabic), al-Khawarizmi’s book was studied in the Islamic mosque-universities in Djenné, Timbuktu, and in many parts of the Arabic-speaking world then and, in translation, since. It also made a significant impact in medieval Europe.

Numerals, Place-Values, and Algorithm. In another volume, On the Calculation of Hindu Numerals (circa 825), now lost except in a Latin translation (Algoritmi de numero Indorum), al-Khawarizmi also provided the Middle East, North and West African Arabic-speaking areas, and Europe (through translators) with the tools to use Hindu-Arabic numerals, including zero, and place-values. Algorithm, a term derived from an abbreviated version of the author’s last name, is used today to describe a mathematical procedure for solving a problem in the shortest effective way, by a finite number of steps that involves the repetition of a specific operation.

Other Works. Another of al-Khawarizmi’s important works includes a text on astronomy, based on an Indian treatise given to the Baghdad court around 770. He evidently used the ancient scholar Ptolemy’s data for a major work on geography. It listed latitudes and longitudes for more than 2,400 localities, and in many regards it was more accurate than Ptolemy’s determinations.

Sources

Leonard C. Bruno, “Al-Khwarizmi,” in Math and Mathematicians: The History of Math Discoveries around the World, volume 1, edited by Lawrence W. Baker (Detroit, Mich.: UXL, 1999), p. 18.

J. J. O’Connor and E. F. Robertson, “Abu Ja’far Muhammad ibn Musa Al-Khwarizmi” (27 May 2003) <http://www.history.mcs.st-andrews.ac.uk/history/References/Al-Khwarizmi.html>

PBS, “Islam: Empire of Faith, Algebra and Trigonometry” (24 November 2002) <http://www.pbs.org/empires/Islam/innoalgebra.html>.