The inventor of algebra, Muhammad ibn Musa al-Khwarizmi (c. 780–c. 850) was a Baghdad-based scholar, astronomer, and theologian. His surviving mathematical treatises had an enormous impact on both the Islamic and the Christian worlds. Among other accomplishments, he is known for devising algorithms and popularizing the system of Arabic numerals whose use prevails across the world today.

Al-Khwarizmi was thought to have been born in modern-day Uzbekistan, but spent most of his life in Baghdad, then the capital of the Islamic world. He was a member of the House of Wisdom, the caliphate’s leading intellectual institution. Sitting at the cultural crossroads of Europe and Asia, the Baghdad scholars had access to texts from both Hindu mathematicians in the East and ancient Greek thinkers such as Ptolemy and Aristotle in the West.

The algebraic system originated in a book al-Khwarizmi wrote in about 820, Hisab al-jabr w’al-muqabala (Handbook for Calculation by Completing and Balancing). Al-jabr, meaning “completion” in Arabic, eventually became the word algebra in English.

At some later point, al-Khwarizmi wrote On the Hindu Art of Reckoning, which endorsed the use of the Hindu numeral system. The book became famous in his lifetime: Copies were circulated in Spain, then under Islamic control, and from there it spread to Christian Europe, where the numbers soon replaced Roman numerals. (Confusingly, the numerals are often referred to as Arabic numerals, even though al-Khwarizmi made it clear that the system originated in India.)

Al-Khwarizmi also studied Islamic astronomy, geography, and religious law. His most famous works were dedicated to the caliph al-Ma’mun (786–833), a keen supporter of the House of Wisdom and a major figure in Baghdad’s golden age of learning.

ADDITIONAL FACTS

  1. The word algorithm—meaning a rule of calculation in mathematics—is derived from an early Latin translation of al-Khwarizmi’s name.
  2. Many of al-Khwarizmi’s original works were lost when Baghdad was sacked by the Mongols in 1258. The invaders destroyed the House of Wisdom and, according to legend, threw its library into the Tigris River.
  3. Although algebra is derived from al-Khwarizmi’s work, his original treatise on the topic does not contain any algebraic equations. He explained his ideas only in words, without using symbols or numerals.

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