18 May 2019
Omar Khayyam was a Persian astronomer, writer, poet and mathematician renowned in Iran for his scientific achievements.
English-speaking readers know of his extraordinary work through the translation of his collection of hundreds of quatrains (or Rubais) in Rubaiyat, an 1859 work on the "the Astronomer-Poet of Persia".
In his honour, Google has changed its logo into a dedicated animation, or doodle, in 17 countries with an image highlighting Khayyam and his most important achievements.
But in his lifetime, the scientist and writer was not always appreciated for his work.
This is his story:
Omar Khayyam was born on May 18 in the trading city of Nishapur in what today is known as Iran in the year 1048.
Khayyam's father was Ebrahim Khayyami, a wealthy physician, his mother's name remains unknown.
His origins are still unclear but some authors have argued that Omar's father earned a living by being merchant and making tents, as his last name means tent-maker.
Khayyam's family were Muslims, but his father was perceived as non-strict, he soon employed mathematician Bahmanyar bin Marzban, a devotee of the ancient Persian religion or Zoroastrianism, to tutor Omar.
Khayyam's received a thorough education in science, philosophy and mathematics.
In 1066, when Khayyam celebrated his 18th birthday, his father Ebrahim died just a few months before his tutor's death.
These events marked the end of an era in the young pupil's life, and after putting his family's affairs in order, he moved on.
The Rise Of A Scientist
Khayyam joined one of the regular caravans making a three-month journey from Nishapur to the city of Samarkand, which is now in Uzbekistan.
In Samakarn, he showed a remarkable interest in mathematics, by writing treatises on arithmetic, algebra, and music theory under the patronage of chief justice Abu Tahir, who was also his father's friend, and who noticed Khayyam's extraordinarily talent with numbers.
It is presumed that due to his relationship with Tahir, ruler Shams al-Mulk distinctively regarded Omar with esteem.
According to reports the ruler used to show him the greatest honour, so much so that he would make Khayyam sit next to him on his divan.
Probably he was still at Shams al-Muk's court around 1073 when peace was concluded with Sultan Malik Shah, who had earlier invaded the territory.
It was then at the age of 26 that Khayyam entered Malik Shah's service and when he was invited to go back to Iran to build an observatory at Isfahan and reform the Persian calendar.
Privileged lifestyle in Iran
He remained in Iran for the next 18 years, where he was paid an extraordinary high salary and enjoyed a privileged lifestyle.
During this time the scientist measured the length of a year - tropical year length - with remarkable precision.
Recalibrating the calendar fixed the first day of the year at the exact moment of the passing of the Sun's centre across the equinox.
Shah introduced Khayyam's calendar, the Jalali calendar, on March 15, 1079, the scientist was 31 years old,
This calendar was used until the 20th century in Iran, he is also believed to have built models illustrating the theory of the Earth's revolution on its axis.
The various biographical extracts refer to him as unequalled in scientific knowledge and achievement during his time.
His memory was prodigious, according to Omar's contemporary biographer, al-Bayhaqi.
According to the author he was able to memorise a whole book after reading it several times, when he returned the book, the scientist was able to rewrite it from memory showing remarkable resemblance.
He was also a well-established mathematician, and his surviving mathematical works include: A commentary in the difficulties concerning the postulates of Euclid's Elements, on the division of a quadrant of a circle, and on proofs for problems concerning algebra.
During Sultan Malik Shah's life both shared a great relationship however his luck changed when his successor, Sultan Sanjar entered to power.
Sultan Sanjar did not favour the scientist, it seems that Omar offended Sanjar while he was still a child, and he was never forgiven.
Upon Malik Shah's death, Khayyam had fallen from favour at court and funding for raising the observatory eventually finished.
He went on a pilgrimage to Mecca and visited Baghdad. In his return he retired to Nishapur, where he appeared to have lived the life of a recluse.
Among his other contributions, Khayyam is also best known for his work as a poet.
The Rubaiyat was his collection of hundreds of quatrains, and it was first translated from Farsi to English in 1859 by Edward Fitzgerald.
The poems celebrated the pleasures of life while illuminating the nuanced political and religious context in which they were created.
Some scholars believed that the scientist and author penned around 150 of the quatrains; other writers after him are thought to have contributed to the remainder.
He died in Nishapur at the age of 83, on December 4, 1131. From an account of Nizami Arudi, a Persian poet, Omar used to say that his "grave will be in a spot where the trees will shed their blossoms on me twice a year".
When Arudi visited Nishapur about four years after Omar's death, he searched for Omar's grave, it was exactly at the spot where Omar had predicted.
According to the narration the blossoms completely covered the tombstone.
In 1963, the Shah of Iran ordered Khayyam's grave exhumed and his remains moved to a mausoleum in Nishapur where tourists could pay their respects.
Not enough is known about Khayyam's life but he is believed to have had a wife and two children; a boy and a girl.