OMAR KHAYYAM. The great Persian mathematician, astronomer, freethinker, and epigrammatist, Ghiyhthuddin Abulfath 'Omar bin Ibrahim al-Khayyami, who derived the epithet Khayyam (the tentmaker) most likely from his father's trade, was born in or close by NishapUr, and is stated to have died there in 517 A.H. (1123 A.D.).

This date is accepted by most Eastern and 'Western writers, but the renowned vizier of the Seljuk sultans Alp Arslan and Malikshah, Nizhm-ulmulk of Ms, whose birth is fixed in 408 A.H. (1017 A.D.), expressly states in one of his writings that 'Omar was of the same age as himself, and attended with him the lectures of the imam Muwaffal in the college of NishapUr. However that may be, there cannot be the slightest doubt that at an early age 'Omar entered into a close friendship both with Nizam-uhnulk and his schoolfellow Hasan ibn Sabbah, who founded afterwards the terrible sect of the 'sr/la:ills or Assassins. The three friends pledged themselves by a solemn promise that he who should first gain an influential position in the world would lend a helping hand to the other two and promote their success in life. 'When Nizhm-ulmulk was raised to the rank of vizier by Alp Arslan (1063-1073 A.D.) he remembered this covenant and bestowed upon Hasan ibn Sabbab the dignity of a chamberlain, whilst offering a similar court office to 'Omar Khayyam. But the latter contented himself with an annual stipend which would enable him to devote all his time to his favourite studies of mathematics and astronomy, and he soon proved his gratitude for the liberality of his patron and friend by the publication of his standard work on algebra, written in Arabic. This and other treatises of a similar character - for instance, on the extraction of cube roots and on the explanation of difficult definitions in Euclid - raised him at once to the foremost rank among the mathematicians of that age, and induced Sultan Malikshah to summon him in 467 A.II. (1074 A.D.) to institute astronomical observations on a larger scale, and to aid him in his great enterprise of a thorough reform of the calendar. A twofold fruit resulted from 'Omar's elaborate research in the sultan's observatory, - a revised edition of the Zij or astronomical tables, and the introduction of the Ta'rikh-i-Malikshabi or Jalali, that is, the so-called Jalalian or Seljuk era, which commences in 471 A.H. (1079 A.D., 15th March).

Great, however, as `Omar's scientific fame has always been throughout the East, it is nearly eclipsed by his still greater poetical renown, which he owes to his rubci`is or quatrains, a collection of about 500 epigrams, unequalled by any of his predecessors or followers. The peculiar form of the rubgi - viz., four lines, the first, second, and fourth of which have the same rhyme, while the third usually (but not al- ways) remains rhymeless - was first successfully introduced into Persian literature as the exclusive vehicle for subtle thoughts on the various topics of Sac mysticism by the sheikh Abft Sa'id bin Abulkhair,1 but 'Omar differs in its treatment considerably from Abu Said. Although some of his quatrains are purely mystic and pantheistic, most of them bear quite another stamp ; they are the breviary of a radical freethinker, who protests in the most forcible manner both against the narrowness, bigotry, and uncompromising austerity of the orthodox ulemh and the eccentricity, hypocrisy, and wild ravings of advanced Sufis, whom he successfully combats with their own weapons, using the whole mystic terminology simply to ridicule mysticism itself. There is in this respect a great resemblance between him and Hhfiz, but 'Omar is decidedly superior, not so much on account of his priority as for his more concise, more simple, and yet infinitely more energetic style. He has often been called the Voltaire of the East, and cried down as materialist and atheist. As far as purity of diction, fine wit, crushing satire against a debased and ignorant clergy, and a general sympathy with suffering humanity are concerned, 'Omar certainly reminds us of the great Frenchman ; but there the comparison ceases. Voltaire never wrote anything equal to passionate denunciations of a malevolent and inexorable proves that the modern pessimist is by no means a novel creature in the realm of philosophic thought and poetical imagination.

The Leyden copy of 'Omar Khayyam's work on algebra was noticed as far back as 1742 by Gerald Dieerman in the preface to his Specimen calculi fluxionalis; further notices of the same work by Sedillot appeared in the Nouv. Jour. As., 1834, and in vol. xiii. of the Notices at Extraits des MSS. de la Bibl. roy. The complete text, together with a French translation (on the basis of the Leyden and Paris copies, the latter first discovered by M. Libra see his Histoire des sciences mathernatiques en Italie, a 300), was edited by F. Woepcke, EalgCbre d'Omar Alkhayyami, Paris, 1851. Articles on 'Omar's life and works are found in Iteinaud's Geographic d' Aboulfe'da, pref., p. 101 ; Notices et Extraits, ix. 143 sq.; Garcia de Tassy, Note saw lee Itaba'iyat de 'Omar Khaiyam, Paris, 1857 ; and Rieu, Cat. Pers. 'LISS. in the Br. p. 546. The quatrains have been edited at Calcutta, 1836, and Teheran, 1857 and 1862 ; text and French translation by J. B. Nicolas, Paris, 1867 (very incorrect and misleading); a portion of the same, rendered in English verse, by E. Fitzgerald, London, 1859, 1872, and 1879. A new English version was published in Trillmer's " Oriental Series,' 1882, by E. H. Whinfield, and the first critical edition of the text, with translation, by the same, 1883. (H. E.)