Note: Do not rely on this information. It is very old.
Omar Khayyam
Omar Khayyam (Omar the Tentmaker), was born near Nishapur, and was contemporary with Nizam-ul-mulk and Hasan ibn Sabah, founder of the Assassins. When the latter became vizier to Sultan Alp-Arslan he provided for his friends, giving Omar an annual pension. Omar became an eager student of astronomy and mathematics, wrote a treatise on algebra, and at the invitation of the Sultan Malikshah introduced a new calendar, the Jalali, or Seljuk era, which began from March 15, 1079. He is now, however, chiefly remembered as a poet, owing to the translation and amplification of his Rubaigat (quatrains) by Fitzgerald. Omar died about 1123.