Ghiyās al-Dīn Abu al-Fath Omār ibn Ibrāhīm Khayyām Nishābūrī or Omar Khayyam was a Persian poet, mathematician, philosopher and astronomer who lived in Persia in the eleventh century.
While is best known for his poetry in the west in his native Iran he is perhaps better known as a mathematician, astronomer and scientist. His significant mathematical contributions include his Treatise on Demonstration of Problems of Algebra, which gives a geometric method for solving cubic equations by intersecting a hyperbola with a circle. He also contributed to calendar reform and proposed a heliocentric theory well before Copernicus.
Born in what is today northern Iran, he is thought to have been born into a family of tent makers (literally, al-khayyami means "tent maker"). According to legend, Khayyam studied along side Nizam-ul-Mulk, who went on to become the Vizier to the Seljukid Empire, and Hassan-i-Sabah who became the leader of the Hashshashin sect.
Certainly during his life was famous as a mathematician and was very influential in the fields of geometry and algebra. Like most mathematicians of the period, Khayyám was also famous as an astronomer. In 1073, the Seljuk dynasty Sultan Sultan Jalal al-Din Malekshah Saljuqi (Malik-Shah I, 1072-92), invited Khayyám to build an observatory, along with various other distinguished scientists. Khayyám and his colleagues measured the length of the solar year as 365.24219858156 days (correct to six decimal places). He was also influential in changing the Persian calendar which is more accurate than the Gregorian calendar.
Inside Persia, Khayyam, became famous for his demonstration of the motion of the earth. By constructing a revolving platform and simple arrangement of the star charts lit by candles around the circular walls of the room, he demonstrated that the earth revolves on its axis, bringing into view different constellations throughout the night and day, predating Copernicus’ similar assertions by several hundred years.

The Rubaiyat

Rubaiyat is a collection of poems, originally written in Persian. Rubaiyat means four and each poem is a four line quatrain. More than a thousand of these quatrains have been attributed to Khayyam although the collection we know as The Rubaiyat contains just a hundred.
Different translations have selected different poems to support notions about Khayyams philosophy and religious background. Some have seen Khayyam as a devout Muslim while others have seem him as an atheist, mystic or more probably a Sufi.
The best known translation into English are were completed by Edward Fitzgerald in the mid nineteenth century.
As a work of English literature Fitzgerald's poetic version is a high point of the 19th century. Some scholars have pointed to Fitzgerald’s loose interpretation of Khayyam’s words and sarcastically referred to the book as "The Rubaiyat of FitzOmar.