ubáiyát of Omar Khayyám is the title that Edward FitzGerald gave to his 1859 translation from Persian to English of a selection of quatrains (rubāʿiyāt) attributed to Omar Khayyam (1048–1131), dubbed "the Astronomer-Poet of Persia". FitzGerald's work at first was unsuccessful commercially. But it was popularised from 1861 onward by Whitley Stokes, and the work came to be greatly admired by the Pre-Raphaelites in England. In 1872 FitzGerald had a third edition printed, which increased interest in the work in the United States of America. By the 1880s, the book was extremely well known throughout the English-speaking world, to the extent that numerous "Omar Khayyam Clubs" were formed and there was a "fin de siècle cult of the Rubaiyat". FitzGerald's work has been published in several hundred editions, and it has inspired similar translation efforts in English and in many other languages.

In the year 1072 AD, Omar Khayyam documented the most accurate year length ever calculated – a figure still accurate enough for most purposes in the modern world. Khayyam was an astronomer, astrologer, physician, philosopher, and mathematician: he made outstanding contributions in algebra. His poetry is better known in the West than any other non-Western poet.