Editing Omar Khayyam (section)

==Life==
Omar Khayyam was born in [[Nishapur]]—a metropolis in [[Greater Khorasan|Khorasan]] province, of [[Iranian peoples|Persian]] stock, in 1048.<ref name="The Wine of Wisdom" /><ref>{{cite book|last1=Arberry|first1=A.J.|author1-link=Arthur John Arberry|title=Aspects of Islamic Civilization: As Depicted in the Original Texts|date=2008|publisher=Routledge |isbn=978-0-415-42600-8|page=16|quote=Omar composed his shafts of wit and shapes of beauty in his native Persian, which by the tenth century had recovered from the stunning blow dealt it by Arabic.}}</ref><ref name="Al-Khalili">{{Cite book|url=https://books.google.com/books?id=ntLEUHTXxUMC&q=al+mahani+persian+mathematician&pg=PT194|title=Pathfinders: The Golden Age of Arabic Science|last=Al-Khalili|first=Jim|date=30 September 2010|publisher=Penguin UK|isbn=978-0-14-196501-7|quote=Later, al-Karkhi (correct: [[al-Karaji]]), [[Abu Mansur al-Baghdadi|Ibn Tahir]] and the great [[Ibn al-Haytham]] in the tenth/eleventh century took it further by considering cubic and quartic equations, followed by the Persian mathematician and poet Omar Khayyam in the eleventh century.}}</ref><ref name=EI2-Khayyam>{{cite encyclopedia|last1=Fouchécour|first1=Charles-Henri de|last2=Rosenfeld|first2=Boris A.|editor1-last=[[H. A. R. Gibb]]|title=[[Encyclopaedia of Islam]]|edition=2nd|date=1954–2007|orig-date=2000|publisher=Brill |location=Leiden|volume=X|pages=827b–834a|isbn=90-04-07026-5|chapter=ʿUmar K̲h̲ayyām|doi=10.1163/1573-3912_islam_COM_1284|chapter-url-access=subscription|display-editors=etal| chapter-url=http://dx.doi.org/10.1163/1573-3912_islam_COM_1284}}</ref><ref>Peter Avery and John Heath-Stubbs, ''The Ruba'iyat of Omar Khayyam'', (Penguin Group, 1981), 14; "These dates, 1048–1031, tell us that Khayyam lived when the Seljuq Turkish Sultans were extending and consolidating their power over Persia and when the effects of this power were particularly felt in Nishapur, Khayyam's birthplace."</ref> In medieval Persian texts he is usually simply called ''Omar Khayyam''.<ref name="The Cambridge History of Iran"/>{{rp|658}}{{efn|name=PersianName|E.g., in [[Rashid-al-Din Hamadani]],<ref>{{cite journal|last1=Browne|first1=E.G.|author-link=Edward Granville Browne|title=Yet More Light on 'Umar-i-Khayyām|journal=Journal of the Royal Asiatic Society of Great Britain and Ireland|date=1899|volume=XXXI |issue=2|pages=409–420|doi=10.1017/S0035869X00026538|jstor=25208104|s2cid=163490581 |url-access=registration|url=https://www.jstor.org/stable/25208104 }}</ref>{{rp|409}} or in ''Munis al-ahrar''.<ref>{{cite journal|last1=Ross|first1=E.D.|author-link=Edward Denison Ross|title='Omar Khayyam |journal=Bulletin of the School of Oriental Studies|date=1927|volume=IV|issue=3 |pages=433–439 |doi=10.1017/S0041977X00102897|jstor=606948|s2cid=246638673|url-access=registration|url=https://www.jstor.org/stable/606948 }}</ref>{{rp|435}}}} Although open to doubt, it has often been assumed that his forebears followed the trade of tent-making, since ''Khayyam'' means 'tent-maker' in Arabic.<ref name = "Boyle">{{cite journal |last1=Boyle |first1=J.A.|author1-link=John Andrew Boyle|title=Omar Khayyām: Astronomer, Mathematician and Poet |journal=Bulletin of the John Rylands Library |date=1966 |volume=LII |issue=1 |pages=30–45|doi=10.7227/BJRL.52.1.3|url-access=subscription|url=https://doi.org/10.7227/BJRL.52.1.3 }}</ref>{{rp|30}} The historian [[Abu'l-Hasan Bayhaqi|Bayhaqi]], who was personally acquainted with Khayyam, provides the full details of his horoscope: "he was Gemini, the sun and Mercury being in the ascendant[...]".<ref name="Earliest Account of Khayyam">{{cite journal|last1=Ross|first1=E.D.|author1-link=Edward Denison Ross|last2=Gibb|first2=H.A.R.|author2-link=H.A.R. Gibb|title=The Earliest Account of 'Umar Khayyām|journal=Bulletin of the School of Oriental Studies|date=1929|volume=V|issue=3|pages=467–473|doi=10.1017/S0041977X00084615|jstor=607341|s2cid=177947195 |url-access=registration |url=https://www.jstor.org/stable/607341 }}</ref>{{rp|471}}<ref name=Bayhaqi>{{cite journal|last1=Meyerhof |first1=Max|title=ʿAlī al-Bayhaqī's Tatimmat Siwān al-Hikma: A Biographical Work on Learned Men of the Islam|journal=Osiris|date=1948|volume=VIII|pages=122–217|doi=10.1086/368514 |jstor=301524|url-access=registration |url=https://www.jstor.org/stable/301524 }}</ref>{{rp|172–175, no. 66}} This was used by modern scholars to establish his date of birth as 18 May 1048.<ref name="The Cambridge History of Iran" />{{rp|658}}

[[File:Mausoleum of Omar Khayyám.jpg|thumb|left|alt=Mausoleum of Omar Khayyám|[[Mausoleum of Omar Khayyám|Mausoleum of Omar Khayyam]] in [[Nishapur]], [[Iran]]. Some of his rubáiyáts are used as [[Taliq script|calligraphic (taliq script)]] decoration on the exterior body of his mausoleum.]]

Khayyam's boyhood was spent in Nishapur,<ref name="The Cambridge History of Iran" />{{rp|659}} a leading metropolis in the [[Seljuk Empire]],<ref name = "Sarton">{{cite journal |last1=Sarton|first1=G.|author-link=George Sarton|title=The Tomb of Omar Khayyâm |journal=Isis|date=1938|volume=XXIX|issue=1|pages=15–19|doi=10.1086/347379|jstor=225920|s2cid=143678233 |url-access=registration|url=https://www.jstor.org/stable/225920 }}</ref>{{rp|15}}<ref name = "FitzGerald">Edward FitzGerald, ''Rubaiyat of Omar Khayyam'', Ed. Christopher Decker, (University of Virginia Press, 1997), xv; "The Seljuq Turks had invaded the province of Khorasan in the 1030s, and the city of Nishapur surrendered to them voluntarily in 1038. Thus Omar Khayyam grew to maturity during the first of the several alien dynasties that would rule Iran until the twentieth century".</ref> which had earlier been a major center of the [[Zoroastrianism|Zoroastrian religion]].<ref name="The Wine of Wisdom">{{cite book|last1=Aminrazavi|first1=M.|author-link=Mehdi Aminrazavi|title=The Wine of Wisdom: The Life, Poetry and Philosophy of Omar Khayyam|date=2007|publisher=Oneworld|location=Oxford|isbn=978-1-85168-355-0}}</ref>{{rp|68}} His full name, as it appears in Arabic sources, was ''Abu’l Fath Omar ibn Ibrahim al-Khayyam''.{{efn|name=ArabicName|In e.g., [[al-Qifti]],<ref name="The Wine of Wisdom" />{{rp|55}} or [[Abu'l-Hasan Bayhaqi|Bayhaqi]].<ref name="Earliest Account of Khayyam"/>{{rp|463}}<ref name=Bayhaqi/>{{rp|172–175, no. 66}}}} His gifts were recognized by his early tutors who sent him to study under Imam Muwaffaq Nishaburi, the greatest teacher of the Khorasan region who tutored the children of the highest nobility, and Khayyam developed a firm friendship with him through the years.<ref name="The Wine of Wisdom" />{{rp|20}} Khayyam might have met and studied with [[Bahmanyar]], a disciple of [[Avicenna]].<ref name="The Wine of Wisdom" />{{rp|20–21}} After studying science, philosophy, mathematics and astronomy at Nishapur, about the year 1068 he traveled to the province of [[Bukhara]], where he frequented the renowned library of the [[Ark of Bukhara|Ark]]. In about 1070 he moved to [[Samarkand]], where he started to compose his famous ''[[#Mathematics|Treatise on Algebra]]'' under the patronage of Abu Tahir Abd al-Rahman ibn ʿAlaq, the governor and [[Qadi|chief judge]] of the city.<ref name=Rosenfeld>{{cite encyclopedia|last1=Rosenfeld|first1=Boris A.|editor1-last=[[Helaine Selin]]|title=Encyclopaedia of the History of Science, Technology, and Medicine in Non-Western Cultures|date=2016|publisher=Springer–Verlag |location=Dordrecht |isbn=978-94-007-7747-7|doi=10.1007/978-94-007-7747-7_9775|pages=4330b–4332a|edition=3rd|chapter=Umar al-Khayyām|chapter-url-access=subscription|chapter-url=https://doi.org/10.1007/978-94-007-7747-7_9775 }}</ref>{{rp|4330b}} Khayyam was kindly received by the Karakhanid ruler [[Kara-Khanid Khanate#Monarchs|Shams al-Mulk Nasr]], who according to Bayhaqi, would "show him the greatest honour, so much so that he would seat [Khayyam] beside him on his [[divan|throne]]".<ref name="Boyle"/>{{rp|34}}<ref name="The Wine of Wisdom"/>{{rp|47}}

In 1073–4 peace was concluded with [[Sultan]] [[Malik-Shah I]] who had made incursions into Karakhanid dominions. Khayyam entered the service of Malik-Shah in 1074 when he was invited by the [[vizier|Grand Vizier]] [[Nizam al-Mulk]] to meet Malik-Shah in the city of [[Merv|Marv]]. Khayyam was subsequently commissioned to set up an observatory in [[Isfahan]] and lead a group of scientists in carrying out precise astronomical observations aimed at the revision of the Persian calendar. The undertaking probably began with the opening of the observatory in 1074 and ended in 1079,<ref name="The Wine of Wisdom"/>{{rp|28–29}} when Omar Khayyam and his colleagues concluded their measurements of the length of the year, reporting it as 365.24219858156 days.<ref name=mactutor/> Given that the length of the year is changing in the sixth decimal place over a person's lifetime, this is outstandingly accurate. For comparison, the length of the year at the end of the 19th century was 365.242196 days, while today it is 365.242190 days.

After the death of Malik-Shah and his vizier (murdered, it is thought, by the [[Ismaili]] [[order of Assassins]]), Khayyam fell from favor at court, and as a result, he soon set out on his [[Hajj|pilgrimage to Mecca]]. A possible ulterior motive for his pilgrimage reported by [[Al-Qifti]], was a public demonstration of his faith with a view to allaying suspicions of skepticism and confuting the allegations of unorthodoxy (including possible sympathy or adherence to Zoroastrianism) levelled at him by a hostile clergy.<ref name="The Wine of Wisdom" />{{rp|29}}<ref name="The Wine of Wisdom" />{{rp|29}}<ref>{{Cite journal|last=Aminrazavi|first=M.|author-link=Mehdi Aminrazavi|date=2010|title=Review: Omar Khayyam: Poet, Rebel, Astronomer, Hazhir Teimourian|journal=Iranian Studies|volume=XLIII|issue=4|pages=569–571|jstor=23033230|doi=10.1080/00210862.2010.495592|s2cid=162241136|url-access=registration|url=https://www.jstor.org/stable/23033230 }}</ref> He was then invited by the new [[Sultan Sanjar]] to Marv, possibly to work as a court [[astrologer]].<ref name="Britannica"/> He was later allowed to return to Nishapur owing to his declining health. Upon his return, he seems to have lived the life of a recluse.<ref name="Great Muslim Mathematicians">{{cite book|last1=Mohamed|first1=Mohaini|title=Great Muslim Mathematicians|date=2000|publisher=Penerbit Universiti Teknologi Malaysia|location=Malaysia|isbn=983-52-0157-9}}</ref>{{rp|99}}

Omar Khayyam died at the age of 83 in his hometown of Nishapur on 4 December 1131, and he is buried in what is now the [[Mausoleum of Omar Khayyám|Mausoleum of Omar Khayyam]]. One of his disciples [[Nizami Aruzi]] relates the story that sometime during 1112–3 Khayyam was in [[Balkh]] in the company of [[Al-Isfizari|Isfizari]] (one of the scientists who had collaborated with him on the Jalali calendar) when he made a prophecy that "my tomb shall be in a spot where the north wind may scatter roses over it".<ref name="Boyle"/>{{rp|36}}<ref name="FitzGerald"/> Four years after his death, Aruzi located his tomb in a cemetery in a then large and well-known quarter of Nishapur on the road to Marv. As it had been foreseen by Khayyam, Aruzi found the tomb situated at the foot of a garden-wall over which pear trees and apricot trees had thrust their heads and dropped their flowers so that his tombstone was hidden beneath them.<ref name="Boyle"/>{{rp|37}}