Omar Khayyam (1048–1131) was a Persian poet and polymath, known for his contributions to mathematics, astronomy, philosophy, and Persian literature. He was born in Nishapur, Iran and lived during the Seljuk era, around the time of the First Crusade.

As a mathematician, he is most notable for his work on the classification and solution of cubic equations, where he provided a geometric formulation based on the intersection of conics. He also contributed to a deeper understanding of Euclid's parallel axiom. As an astronomer, he calculated the duration of the solar year with remarkable precision and accuracy, and designed the Jalali calendar, a solar calendar with a very precise 33-year intercalation cycle which provided the basis for the Persian calendar that is still in use after nearly a millennium.

There is a tradition of attributing poetry to Omar Khayyam, written in the form of quatrains (rubāʿiyāt رباعیات). This poetry became widely known to the English-reading world in a translation by Edward FitzGerald (Rubaiyat of Omar Khayyam, 1859), which enjoyed great success in the Orientalism of the fin de siècle.