This individual's full name is Abu Abdullah Mohammad Ibn Musa al-Khawarizmi (which translates as Abu Abdullah Mohammad, son of Moses, from Kwawarizm). His name is also found spelled as Al Khuwārizmĩ, Alkarizmi, al-Khowarizmi, Muhammad Al-Khorezmi, Mohammed ben Muja Alkarismi, the differences probably being caused by translation of his Arab name into Western language. For simplicity, let us call him Alkarismi.

Alkarismi was an Arab mathematician, astronomer and geographer who lived around the year 800 A.D. The precise dates of his birth and death are not known, but it is believed he was born circa 780 in Khawarizm (today Kheva), south of the Aral sea, in an area which is today's Uzbekistan. He probably died around 850 A.D.

Alkarismi
migrated with his parents to Baghdad which was a major cultural centre at
that time. Here he became a math teacher and served the Caliph Al-Mamun as
court astronomer. As geographer he produced the first map of the known world in
830 A.D. His knowledge and understanding of mathematics enabled him to
synthesise Greek and Hindu knowledge of numbers and calculation when he
published his famous book *Al-Maqala fi Hisab Al-Jabr wa-al-Muqabalah *
("the book of calculation, transposition and cancellation").
From the word *Al-Jabr *("transposition")
in the title we get our word *Algebra.* His book described the basic
algebraic technique of transferring a positive term on one side of the equation
sign to the other side (where it becomes negative) and the reduction of several
similar algebraic terms to one term (*al-Muqabalah*). Another concept he
explained in detail in his book was the use of zero, a numeral of enormous
importance in mathematics and science as it enables the concept of a positional
value. The concept of the numeral zero was already developed in the Arab world,
but till then unknown in the Western world. He also developed the overall
system of decimal numerals, *algorismi*, based on the Indian numerals as
well as several arithmetical procedures, including how to do fractions and the
analytical solutions of linear and quadratic equations. This has made him the
founding father of *Algebra.*

His book was
translated into Latin in the 12^{th} century and it was this translation
that introduced this completely unknown branch of mathematics to the Western
world. Several of his books have been translated and became the Western
university reference books till the 16^{th} century. His works have
been instrumental in introducing algebra and the use of Hindu-Arabic numerals
into European mathematics.

In the words of
Phillip Hitti: *"He influenced mathematical thought to a greater extent
than any other mediaeval writer."*

*USSR Postal Stationery with additional franking for Registration,
from Tashkent to Leningrad, commemorative canceller reads:
1200 Years Anniversary of Birth Mohammed Al-Karismi 06-09-1983.
*

His role in the
modern field of computers lies in the word *algorithm *which was derived
from the Latinised version of his name. An *algorismi *or *algorismus*
– later *algorism* – originally was a method of written calculation using
Indian-Arabic numerals, as opposed to methods based on the use of an abacus,
which had been the main calculating device at that time. The word *algorithm*
ultimately acquired a more general and abstract meaning. In science an algorithm is a finite number of
well-defined steps for the systematic solution of a problem. A computer program
is basically an algorithm as it defines the steps or procedures to be carried
out to solve a problem.

**
© Wobbe Vegter, April 2005**