Nasir
AdDin Tusi 
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Tusi Nasir
adDin (b. Feb. 18, 1201, Tus, Khorasand. June 26, 1274, Baghdad), outstanding Persian
philosopher, scientist, and mathematician.
Tusi became astrologer to the governor Nasir adDin 'Abd arRahim.
He made significant contributions to mathematics and
astronomy; his Ziji Ilkhani is a splendidly accurate table of planetary movements.
His most famous and popular work is
the Akhlaq Nasiri, resting upon the 11thcentury Tahdhib
alakhlaq of Ibn Miskawayh, which he drafted while a prisoner of the Assassins and later revised
for his Mongol master. This work has been translated into English. He made
important contributions to many branches of Islamic learning and wrote in excellent philosophical
prose.

Abu
ArRayhan Mohammad ibn Ahmad AlBiruni 
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AlBiruni,
in full ABU ARRAYHAN MUHAMMAD IBN AHMAD ALBIRUNI (b. September 973,
Khwarezm, Khorasand. Dec. 13, 1048, Ghazna, Ghaznavid Afghanistan [now
Ghazni, Afg.]), Persian scholar and scientist, one of the most learned men of his age and an outstanding intellectual
figure.
Possessing a profound and original mind of encyclopaedic scope, alBiruni was conversant with
Turkish, Persian, Sanskrit, Hebrew, and Syriac in addition to the Arabic in which he wrote. He
applied his talents in many fields of knowledge, excelling particularly in astronomy, mathematics,
chronology, physics, medicine, and history. He corresponded with the great philosopher Ibn Sina
(Avicenna). Some time after 1017 he went to India and made a comprehensive study of its culture.
Later he settled at Ghazna in Afghanistan.
AlBiruni's most famous works are Athar albaqiyah (Chronology of Ancient Nations);
atTafhim ("Elements of Astrology"); alQanun alMas'udi ("The Mas'udi Canon"), a major work
on astronomy, which he dedicated to Sultan Mas'ud of Ghazna; Ta'rikh alHind ("A History of
India"); and Kitab asSaydalah, a treatise on drugs used in medicine. In his works on astronomy,
he discussed with approval the theory of the Earth's rotation on its axis and made accurate
calculations of latitude and longitude. In those on physics, he explained natural springs by the laws of
hydrostatics and determined with remarkable accuracy the specific weight of 18 precious stones
and metals. In his works on geography, he advanced the daring view that the valley of the Indus had
once been a sea basin.

Omar
Khayyam 
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Omar Khayyam,
Arabic in full GHIYATH ADDIN ABU ALFATH 'UMAR IBN IBRAHIM
ALKHAIYAMI ANNISHABURI, Persian ABU OLFATH 'OMAR EBN EBRAHIM
OLKHAYYAMI (b. May 18, 1048, Nishapur, Irand. Dec. 4, 1131, Nishapur), Persian poet,
mathematician, and astronomer, renowned in his own country and time for his scientific
achievements but known to Englishspeaking readers for his roba'iyat ("quatrains") in the
version The Rubayat of Omar Khayyلm, published in 1859 by Edward FitzGerald (q.v.).
He later lived in Samarkand and Esfahan, and his brilliant
work there continued many of the main lines of development in 19thcentury mathematics. Not only
did he discover a general method of extracting roots of arbitrary high degree, but his Algebra
contains the first complete treatment of the solution of cubic equations. Omar did this by
means of conic sections, but he declared his hope that his successors would succeed where he had
failed in finding an algebraic formula for the roots.
Omar was also a part of an Islamic tradition, which included Thabit and Alhazen, of investigating
Euclid's parallel postulate. To this tradition Omar contributed the idea of a quadrilateral with
two congruent sides perpendicular to the base. The parallel postulate would be proved, Omar
recognized, if he could show that the remaining two angles were right angles. In this he failed, but his
question about the quadrilateral became the standard way of discussing the parallel postulate.
That postulate, however, was only one of the questions on the foundations of mathematics that
interested Islamic scientists. Another was the definition of ratios.
In fact, Omar argued that ratios should be regarded as "ideal numbers," and so he conceived of a
much broader system of numbers than that used since Greek antiquity, that of the positive real
numbers.
His name Khayyam ("Tentmaker") may have been derived from his father's trade. He received a
good education in the sciences and philosophy in his native Neyshabur (Nishapur) and in Balkh and
then went to Samarkand, where he completed an important treatise on algebra. He made such a
name for himself that he was invited by the Seljuq sultan MalikShah to undertake the
astronomical observations necessary for the reform of the calendar. He was also commissioned to
build an observatory in the city of Esfahan in collaboration with other astronomers. After the death
of his patron in 1092, Omar went on a pilgrimage to Mecca. Returning to Neyshabur he taught and
served the court from time to time by predicting events to come. Philosophy, jurisprudence, history,
mathematics, medicine, and astronomy are among the subjects mastered by this brilliant man.
Unfortunately, few of his prose writings survive; these include a few brief tracts on metaphysics and
a treatise on Euclid.

Abu AlQasim Khalaf ibn Abbas AzZahrawi (Albucasis) 
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Abu alQasim, also spelled ABUL KASIM, in full ABU ALQASIM KHALAF IBN 'ABBAS
AZZAHRAWI, Latin ALBUCASIS (b. c. 936, near Cَrdoba [Spain]d. c. 1013), Islam's
greatest medieval surgeon, whose comprehensive medical text, combining Middle Eastern and
GrecoRoman classical teachings, shaped European surgical procedures until the Renaissance.
Abu alQasim was court physician to the Spanish caliph 'Abd arRahman III anNasir and wrote
AtTasrif liman 'ajaz'an atTa`alif, or AtTasrif ("The Method"), a medical work in 30 parts.
The last chapter, with its drawings of more than 200 instruments, constitutes the first illustrated, independent work on surgery.
Although AtTasrif was largely ignored by physicians of the eastern Caliphate, the surgical treatise
had tremendous influence in Christian Europe. Translated into Latin in the 12th century by the
scholar Gerard of Cremona, it stood for nearly 500 years as the leading textbook on surgery
in Europe, preferred for its concise lucidity even to the works of the classic Greek medical authority
Galen.

Ibn al'Awwam 
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An agriculturist who wrote the Arabic treatise on agriculture,
Kitab alfila hah, the outstanding medieval work on the subject. The Spanish translation,
published in the early 1800s, consists of 35 chapters dealing with agronomy, cattle and poultry
raising, and beekeeping. It deals with 585 plants; explains the cultivation of more than 50 fruit trees;
and includes many valuable observations on soils, manures, plant grafting, and plant diseases.
