Abu Jafar Muhammad ibn Musa al-Khwarizmi

A postage stamp issued by the USSR in 1983 to commemorate the 1200th anniversary of Muhammad al-Khowarizmi, after whom algorithms are named.

Some Russian artist's impression of what al-Khwarizmi looked like? I suppose Hollywood did choose Charlton Heston for Moses.

This image comes from Donald Knuth's home page.

The following from Karl Menninger's Number Words and Number Symbols: A Cultural History of Numbers, 1958 (MIT Press 1977, pages 410-412)

Al-Khwarizmi and Algorithmus

In 773 there appeared at the court of the Caliph al-Mansur in Baghdad a man from India who brought with him the writings on astronomy (the Siddhanta) of his compatriot Brahmagupta (fl. ca. AD 600). Al-Mansur had this book translated from Sanskrit into Arabic (in which it became known as the Sindhind). It was promptly disseminated and induced Arab scholars to pursue their own investigations into astronomy.

One of these was Abu Jafar Muhammad ibn Musa al-Khwarizmi, "Mohammed the father of Jafar and the son of Musa, the Khwarizmian" (from the Persian province of Khoresm, south of the Aral Sea, which the Greeks had called Khorasmia). This man, who was probably the greatest mathematician of his time, wrote among other things a small textbook on arithmetic in which he explained the use of the new Indian numerals [0 1 2 3 4 5 6 7 8 9], as he had probably learned them himself from the Indian writings. This was around A.D. 820.

Muhammad ibn Musa al-Khwarizmi was also the author of a book showing how to solve equations and problems derived from ordinary life, entitled Hisab aljabr w'almuqabala, "The Book of Restoration and Equalization" (that is, expressions arrived at in the course of solving equations). Its translation into Latin, Algebra et Almucabala, in the 12th century, then ultimately gave its name to the discipline of algebra.

The original of al-Khwarizmi's book on arithmetic is lost, but it still occupies an important place in the history of our numerals, for it made its way to Spain by the route already sketched out [Arabia, through Egypt and North Africa and across the Straights of Gibraltar] and it was there that it was translated into Latin by the Englishman Robert of Chester, who "read mathematics" in Spain. Another Latin version was produced by the Spanish Jew, John of Seville. Robert's translation is the earliest known introduction of the numerals into the West. The manuscript, discovered in the 19th century, begins with the words:

Dixit Algoritmi: laudes deo rectori nostro atque defensori dicmus dignas

Algoritmi has spoken: praise be to God, our Lord and Defender.

At about the same time (around 1143) an epitome of this book was written which is now in the Royal Library in Vienna; the illustration of Fig. 249 is taken from this. [Fig. 249 A multiplication table from 1 x 1 through 9 x 9, from one of the oldest German algorism manuscripts, from the 12th century.] The Codex of the Salem monastery is also one of the oldest witnesses to the presence of al-Khwarizmi's book in the Germanic part of Europe; its origin has been placed around the year 1200. [Fig 232 The Salem manuscript of the 12th century is one of the oldest in the West in which computations are described with Indian numerals. 15 pages. University Library, Heidelberg.] This Salem Codex begins (in very abbreviated Latin):

Incipit liber algorithmi: omnis sapientia sive scienta a domine Deo; sicut scriptum est: Hoc quod continent omnia scientiam habet, et iterum: Omnia in mensura et pondere et numero constituisti, "

Here begins the book of Algorithmus. All wisdom and all knowledge comes from God our Lord; as it is written [referring to Ecclesiastes 1:7]: that which embraces all things is full of wisdom, and further: thou hast established all things by measure and weight and number

But al-Khwarizmi, or Algorismus as he was known in Latin, had not only spoken but also given his own name to the new art of computation, as we learn from the Carmen de Algorismo, "Song of the Algorismus"

The French Minorite friar Alexander de Villa Dei, who taught in Paris around 1240, taught the methods of computation with the new numerals in two hundred forty-four widely read (but not always very good) verses of dactylic hexameter. In his version an Indian king named Algor figures as the inventor of the new "art", which itself is called the algorismus. In this manner the word "algorithm" was tortuously derived from Muhammad's surname al-Khwarizmi, and has remained in use to this day in the sense of an arithmetic operation.