Omar Khayyam

In his own lifetime Omar Khayyam of Nishapur was celebrated as a mathematician and astronomer, among the leading scientists of the Seljuk age. He produced the first systematic geometric treatment of cubic equations and led the team that created the remarkably accurate Jalali calendar. In the modern world he is better known as a poet, thanks to Edward FitzGerald's 1859 English version of the quatrains attributed to him, though how many of those verses he actually wrote is one of the great open questions of Persian literature.

Omar was born in Nishapur, in the Khorasan region of the Seljuk Empire, in today's Iran. A horoscope recorded by the historian Bayhaqi, who knew him, has allowed scholars to fix his birth on 18 May 1048. His name Khayyam means "tent-maker", which may or may not reflect the family trade. After a religious and literary education he turned to mathematics and astronomy, including Ptolemy's Almagest, and he regarded himself as a follower of the philosopher Avicenna. Around 1068 he went to Bukhara, and around 1070 to Samarkand, where the Karakhanid ruler honoured him and he began his Treatise on Algebra.

Khayyam's algebra classified all equations up to the third degree. He identified fourteen kinds of cubic equation that cannot be reduced to simpler ones and showed how to find their positive roots geometrically, as the intersection of two conic sections, while admitting that a purely arithmetical solution still eluded him; it came only with Italian mathematicians in the 16th century. His commentary on Euclid, completed in 1077, examined the parallel postulate through a four-sided figure later studied by Girolamo Saccheri, and so anticipated questions behind non-Euclidean geometry. He also discussed the nature of ratios and irrational numbers.

In 1074 the grand vizier Nizam al-Mulk brought Khayyam into the service of Sultan Malik-Shah I, who commissioned an observatory at Isfahan to reform the calendar. Khayyam's team measured the length of the year with striking precision, and the resulting Jalali calendar, named after the sultan, came into force on 15 March 1079. It began the year at the spring equinox and used a 33-year leap-year cycle that was more accurate than the later Gregorian calendar. Revised in 1925, it underlies the calendar still used in Iran.

After the deaths of Malik-Shah in 1092 and of his vizier, who was probably murdered by the Ismaili Assassins, Khayyam lost favour at court. He made the pilgrimage to Mecca, according to the biographer al-Qifti partly to dispel accusations of impiety, later worked for Sultan Sanjar at Marv, and eventually returned to Nishapur, where he died on 4 December 1131. His tomb there became the site of a modern mausoleum.

Quatrains, or rubaiyat, credited to Khayyam appear in sources from the decades after his death, and a younger contemporary already described him as a poet. But the number attributed to him grew steadily: one 15th-century manuscript in Oxford contains 158. Since short quatrains were a common pastime of scholars, many verses circulated under famous names. Scholars such as Hans Heinrich Schaeder have doubted that any can be securely assigned to him, and Edward Granville Browne judged that few attributions could be proven. Readings of the poems also clash: some see a sceptical, hedonist freethinker, others Sufi metaphor, while his surviving prose works on philosophy are explicitly theistic. Some Sufis of the following century, including Shams of Tabriz, the teacher of Rumi, disliked him.

FitzGerald's free English rendering, based mainly on the Oxford manuscript, sold poorly at first but became a sensation by the 1880s, inspiring Omar Khayyam clubs and hundreds of editions. FitzGerald insisted that the wine in the verses was literal, and some critics blame his version for Khayyam's reputation as a hedonist; later translations are generally more literal. The poem nonetheless revived interest in Khayyam in Iran itself.

Our 1100 map shows the Seljuk lands in which Khayyam spent his career, from Samarkand and Marv to Isfahan and his native Nishapur.