Mathematician
(B. 795 - D. 850). At the end of 8th century, in 795 he was born in Harizm (south to Aral Sea,
the city known as Hive today). In
Latin resources his name is Alkarismi, Algoritmi, Algorismi or Algorism. The famous scientist Prof. Mehmet Fatih
Gökmen preferred to call him “Harezmi” and again other scientists like Prof. Hamit Dilgan preferred to talk about him by making
his name more Turkish as “Harzemli”. Due
to the name resemblance, most of the time he was confused with Ebû Ca’fer
Muhammed b. Mûsâ of Benî Mûsâ brothers and with Ebû
Abdullah Muhammed b. Ahmed el-Hârizmî, the author of Mefâtîhu’l-Ulûm.
Muhammed
bin Musa el Harizmî worked at the library of Beytü’l-Hikme of which he was one
of the important members during the Caliph Me’mûn’s period (813-833). From his works that reached today, it is understood
that he wrote his books in that period and presented them to the Caliph Me’mûn’a . As
per the information from Taberî, Hârizmî
lived during the time of the
Caliph Vâsik and he was in his service. He was with him even when
he died (232/847). Rumor
has it that, the caliph called the famous astrologers including Hârizmî when he
was about to die; and they told the caliph that he would live for another fifty
years according to the astrological calculations they had made, but he died ten
days later. It is considered that Hârizmî died in 850, 17
years later after the Caliph Me’mun. Some of
the manuscripts from his works are at Istanbul Süleymaniye Library.
WORKS:
Zîcü’s-Sind-Hind [Zîcü’l-Hârizmî] (It is based on a book brought to Baghdad by the Indian
committee during the time of the Caliph Mansûr named Brahma-gupta Sidharta or on another book with the same name. Hârizmî added new information to the book with his inventions. It was the first Islamic
astronomy book), Kitâbü’l-Muhtaşar fî hisâbi’l-cebr ve’l-mukâbele (The first
math book that had the “algebra" word in its name compiled methodically. The algebra developed by Hârizmî
was the algebra limited to second-order equation above all. Besides, no negative numbers
were used, so the determination of the equation was only done by finding the
positive roots. Based on
Harizmî’yi- İbn-i Haldun, Kâtip Çelebi was shown as the first
author to write a book on Algebra with Keşf-üz-Zünun), Kitâbü'l-Hisâbi'l-Hindî (The Indian numbers and the decimal number system
was introduced to the Islamic world with this book of Hârizmî), Kitâbü'İ-Cem
ve'l-Tetrîk (This book didn’t
reach today, but it is understood from the reference made by Abdülkâdir b.Tâhir el-Bağdâdî et-Tekmile fi'l-hisâb in his book that this book was about calculation with hands), Kitâbü'l-Coğrafya
[Kitâbü Şûre-ti'l Arz] (This book
of Hârizmî, who was among the first Islamic geographers, gives the coordinates
of the cities and some particular regions. This co-ordination of Hârizmî was a sample for the studies of
the Islamic geographers after him), Risâle
fi'stihrâci târîhi'l-Yehûd (It was a study in which the calendar
used by the Hebrews was discussed within the framework of practical astronomy
understanding. The book
was printed with different booklets on astronomy), Kitâbü't-Târîh (This
book couldn't reach today; however from the references of many Islamic
historians after him, it is understood that like his contemporary Ebû Ma'şer
el-Belhî, Hârizmî also tried to establish a certain relation between the
astrological rules), Kitâbü 'Ameli'l-usturlâb
and Kitâbü l-Amel bi'l-usturlâb (None of them reached
today. Only in a
manuscript correlated to Fergânî, there is a part describing how Hârizmî solved
astronomy problems by using astrolabe method), Amelü's-sâ a fî basîti'r-Ruhâme (The book, found in the classic sources,
is about making a sundial on a marble surface), Zarâ'if min ameli Muhammed b. Mûsâ el-Hârizmî fî ma'rife-ti'ssemt bi'l'usturlâb (A copy of this book, which is not
mentioned in classic sources, reached today. This is most probably a part of an unknown book
of Hârizmî that didn’t reach today).
REFERENCE: Zeki Velidi Togan / Horezm Kültürü Vesikaları I: Horezmce Tercümeli Mukaddimat al-adab (1951), İbrahim Kafesoğlu / Harzemşahlar Devleti Tarihi (1956), Prof. Dr. Hamit Dilgan / Muhammed İbn Musa el- Harzemi (1957), Mehmet Altay Köymen / Büyük Selçuklu İmparatorluğu Tarihi: İkinci İmparatorluk Devri (1984), İsmail Aka / Timur ve Devleti (1991), Ömer Akın - Melek Dosay / Beş Büyük Cebir Bilgini (1994), İhsan Fazlıoğlu / "Cebir" (TDV İslam Ansiklopedisi, c. 7, s. 195-201, 1993) - “Harizmî” (TDV İslam Ansiklopedisi, c.16, s. 224-227, 1997), İhsan Işık / Ünlü Bilim Adamları (Türkiye Ünlüleri Ansiklopedisi, C. 2, 2013) - Encyclopedia of Turkey’s Famous People (2013).
