Iranian cultural officials on Saturday paid tribute to the celebrated Persian philosopher, astronomer, mathematician, and above all poet, Omar Khayyam to honor his 964th birthday anniversary and mark his national day. Khayyam, whose full name is Ghiyath al-Din Abu\'l-Fath Umar ibn Ibrahim Al-Nishapuri al-Khayyami (Omar Khayyam), was born in Nishapur, Northeastern Iran on May 18, 1048. He was a Persian mathematician, astronomer, philosopher and poet. He also wrote treatises on mechanics, geography, and music. Born in Nishapur, at a young age he moved to Samarkand and obtained his education there, afterwards he moved to Bukhara and became established as one of the major mathematicians and astronomers of the medieval period. Recognized as the author of one of the most important treatises on algebra before modern times as reflected in his Treatise on Demonstration of Problems of Algebra giving a geometric method for solving cubic equations by intersecting a hyperbola with a circle. He contributed to a calendar reform. His significance as a philosopher and teacher, and his few remaining philosophical works, have not received the same attention as his scientific and poetic writings. Zamakhshari referred to him as \"the philosopher of the world\". Many sources have testified that he taught for decades the philosophy of Ibn Sina in Nishapur where Khayyam was born and buried and where his mausoleum today remains a masterpiece of Iranian architecture visited by many people every year. Outside Iran and Persian speaking countries, Khayyam has had an impact on literature and societies through the translation of his works and popularization by other scholars. The greatest such impact was in English-speaking countries; the English scholar Thomas Hyde (1636-1703) was the first non-Persian to study him. The most influential of all was Edward FitzGerald (1809-83), who made Khayyam the most famous poet of the East in the West through his celebrated translation and adaptations of Khayyam\'s rather small number of quatrains (rubaiyaas) in Rubaiyat of Omar Khayyam. Mathematician Khayyam was famous during his times as a mathematician. He wrote the influential Treatise on Demonstration of Problems of Algebra (1070), which laid down the principles of algebra, part of the body of Persian Mathematics that was eventually transmitted to Europe. In particular, he derived general methods for solving cubic equations and even some higher orders. Theory of parallels Khayyam wrote a book entitled Explanations of the difficulties in the postulates in Euclid\'s Elements. The book consists of several sections on the parallel postulate (Book I), on the Euclidean definition of ratios and the Anthyphairetic ratio (modern continued fractions) (Book II), and on the multiplication of ratios (Book III). Calendar reform Khayyam is claimed to be a member of a panel that introduced several reforms to the Persian calendar. On March 15, 1079, Sultan Malik Shah I accepted this corrected calendar as the official Persian calendar. This calendar was known as Jalali calendar after the Sultan, and was in force across Greater Iran from the 11th to the 20th centuries. It is the basis of the Iranian calendar which is followed today in Iran and Afghanistan. While the Jalali calendar is more accurate than the Gregorian, it is based on actual solar transit, (similar to Hindu calendars), and requires an Ephemeris for calculating dates. The lengths of the months can vary between 29 and 31 days depending on the moment when the sun crossed into a new zodiacal area (an attribute common to most Hindu calendars). This meant that seasonal errors were lower than in the Gregorian calendar. The modern-day Iranian calendar standardizes the month lengths based on a reform from 1925, thus minimizing the effect of solar transits. Seasonal errors are somewhat higher than in the Jalali version, but leap years are calculated as before. Khayyam built a star map (now lost), which was famous in the Persian and Islamic world. Poet Khayyam\'s poetic work has eclipsed his fame as a mathematician and scientist. He is believed to have written about a thousand four-line verses or rubaiyat (quatrains). In the English-speaking world, he was introduced through the Rubaiyat of Omar Khayyam which are rather free-wheeling English translations by Edward FitzGerald (1809-1883). Other translations of parts of the rubaiyat (rubaiyat meaning \"quatrains\") exist, but FitzGerald\'s are the most well known. Translations exist in languages other than English. Khayyam\'s personal beliefs are not known with certainty, but much is discernible from his poetic oeuvre. Poetry And, as the Cock crew, those who stood before The Tavern shouted - \"Open then the Door! You know how little time we have to stay, And once departed, may return no more.\" Alike for those who for TO-DAY prepare, And that after a TO-MORROW stare, A Muezzin from the Tower of Darkness cries \"Fools! your reward is neither Here nor There!\" Why, all the Saints and Sages who discuss\'d Of the Two Worlds so learnedly, are thrust Like foolish Prophets forth; their Words to Scorn Are scatter\'d, and their mouths are stopt with Dust. Oh, come with old Khayyam, and leave the Wise To talk; one thing is certain, that Life flies; One thing is certain, and the Rest is Lies; The Flower that once has blown for ever dies. Myself when young did eagerly frequent Doctor and Saint, and heard great Argument About it and about: but evermore Came out of the same Door as in I went. With them the Seed of Wisdom did I sow, And with my own hand labour\'d it to grow: And this was all the Harvest that I reap\'d - \"I came like Water, and like Wind I go.\" Into this Universe, and why not knowing, Nor whence, like Water willy-nilly flowing: And out of it, as Wind along the Waste, I know not whither, willy-nilly blowing. The Moving Finger writes; and, having writ, Moves on: nor all thy Piety nor Wit Shall lure it back to cancel half a Line, Nor all thy Tears wash out a Word of it. And that inverted Bowl we call The Sky, Whereunder crawling coop\'t we live and die, Lift not thy hands to It for help - for It Rolls impotently on as Thou or I.