Rubaiyat of Omar Khayyam (Persian: رباعیات عمر خیام) The Rubáiyát (Arabic: رباعیات) is a collection of poems (of which there are about a thousand) attributed to the Persian mathematician and astronomer Omar Khayyám (1048 – 1123). "Rubaiyat" (derived from the arabic root word for 4) means "quatrains": verses of four lines.
The nature of a translation very much depends on what interpretation one places on Khayyam's philosophy. The fact that the rubaiyat are a collection of quatrains - and may be selected and rearranged subjectively to support one interpretation or another - has led to widely differing versions. Nicolas took the view that Khayyam himself clearly was a Sufi. Others have seen signs of mysticism, even atheism, or conversely devout and orthodox Islam. Fitzgerald gave the Rubaiyat a distinct fatalistic spin, although it has been claimed that he softened the impact of Khayyam's nihilism and his preoccupation with the mortality and transience of all things. Even such a question as to whether Khayyam was pro- or anti-alcohol gives rise to more discussion than might at first glance have seemed plausible.
The translations that are best known in English are those of about a hundred of the verses by Edward Fitzgerald (1809-1883).
Of the five editions published, four were published under the authorial control of Fitzgerald. The fifth edition was edited after his death on the basis of manuscript revisions Fitzgerald had left.
Fitzgerald also produced Latin translations of certain rubaiyat.
As a work of English literature Fitzgerald's poetic version is a high point of the 19th century. As a work of accurate line-by-line translation of Omar Khayyam's quatrains, it is noted more for freedom than for fidelity. Many of the verses are paraphrased, and some of them cannot be confidently traced to any one of Khayyam's quatrains at all.
Some critics informally refer to the Fitzgerald's English versions as "The Rubaiyat of FitzOmar", a practice that both recognizes the liberties Fitzgerald inflicted on his purported source and also credits Fitzgerald for the considerable portion of the "translation" that is his own creation. In fact, Fitzgerald himself referred to his work as "transmogrification". Some people find this quite unfortunate. Others see Fitzgerald's translation of the work as being close to the true spirit of the poems.
Perhaps the most famous of Fitzgerald's verses is this one (two versions).
Quatrain XI in his 1st edition:
Quatrain XII in his 5th edition :
This translated quatrain can be traced back to at least two original quatrains that Fitzgerald conflated into one.
Another well-known verse (Fitzgerald's quatrain LI in his 1st edition) is:
The term "Rubaiyat" by itself has come to be used to describe the quatrain rhyme scheme that Fitzgerald used in his translations: AABA.
Adolf Friedrich von Schack (1815-1894) published a German translation in 1878.
Quatrain 151 (equivalent of Fitzgerald's quatrain XI in his 1st edition, as above):
Friedrich Martinus von Bodenstedt (1819-1892) published a German translation in 1881. The translation eventually consisted of 395 quatrains.
Quatrain IX, 59 (equivalent of Fitzgerald's quatrain XI in his 1st edition, as above):
Two English editions by Whinfield (1836-?) consisted of 253 quatrains in 1882 and 500 in 1883.
Quatrain 84 (equivalent of Fitzgerald's quatrain XI in his 1st edition, as above):
The first French translation, of 464 quatrains in prose, was made by J.B. Nicolas, chief interpreter at the French Embassy in Persia in 1867.
Prose stanza (equivalent of Fitzgerald's quatrain XI in his 1st edition, as above):
An English translation of 152 quatrains, published in 1888.
Quatrain I. 20 (equivalent of Fitzgerald's quatrain XI in his 1st edition, as above):
Justin Huntly McCarthy (MP for Athlone) published prose translations of 466 quatrains in 1888.
Quatrain 177 (equivalent of Fitzgerald's quatrain XI in his 1st edition, as above):
Richard Le Gallienne produced a verse translation, subtitled "a paraphrase from several literal translations", in 1897.
Edward Heron-Allen (1861-1943) published a prose translation in 1898. He also wrote an introduction to an edition of Frederick Rolfe (Baron Corvo)’s translation into English of Nicolas’s French translation.
Example quatrain (equivalent of Fitzgerald's quatrain XI in his 1st edition, as above):
The best-known version in French is the free verse edition by Franz Toussaint (1879-1955) published in 1924. This translation consisting of 170 quatrains was done from the original Persian text, while most of the other French translations were themselves translations of Fitzgerald's work. The Éditions d'art Henri Piazza published the book almost unchanged between 1924 and 1979. Toussaint's translation has served as the basis of subsequent translations into other languages, but Toussaint did not live to witness the influence his translation has had.
"In 1959, the distinguished scholar of Persian and Arabic, Professor A. J. Arberry, attempted to make a scholarly edition of Khayyam, relying on thirteenth-century manuscripts. However, those manuscripts were soon to be exposed as twentieth-century forgeries." 
"Arberry’s work, though misguided, had been published in good faith. The alleged translation in 1967 of the Rubáiyat by Robert Graves and Omar Ali-Shah was something more scandalous. This purported to be a translation of a twelfth-century manuscript located somewhere in Afghanistan, where it was allegedly used as a Sufi teaching document. But it proved impossible to produce the manuscript, and British experts in Persian literature had no difficulty in proving that the translation was in fact based on a study of the possible sources of FitzGerald’s work by Edward Heron Allen." 
Quatrain 12 (equivalent of Fitzgerald's quatrain XI in his 1st edition, as above):
A modern version of 235 quatrains, claiming to be "as literal an English version of the Persian originals as readability and intelligibility permit", published in 1979.
Example quatrain 160 (equivalent of Fitzgerald's quatrain XI in his 1st edition, as above):
Like Shakespeare's works, Omar Khayyám's verses have provided later authors with quotations to use as titles:
The British composer Granville Bantock produced a choral setting of Fitzgerald's translation 1906-1909.
Using Fitzgerald's translation, the Armenian-American composer Alan Hovhaness set a dozen of the quatrains to music. This work, The Rubaiyat of Omar Khayyam, Op. 308, calls for narrator, orchestra, and solo accordion.
The artist/illustrator Edmund Dulac produced some much-beloved illustrations for the Rubaiyat, 1909.
The Lebanese writer Amin Maalouf based his story "Samarkand" on the life of Omar Khayyam, and the creation of the Rubaiyat. It details the Assassin sect as well, and includes a telling of how the original book came to be on the Titanic.
Science fiction author Paul Marlowe's story "Resurrection and Life" featured a character who could only communicate using lines from the Rubaiyat.
The Supreme Court of the Philippines quoted The Moving Finger when it junked the election protest of defeated presidential candidate Fernando Poe Jr. against Philippine President Gloria Macapagal Arroyo.
In Cyberflix's PC game, Titanic: Adventure Out of Time, the object is to save three important items, the Rubaiyat of Omar Khayyam, one of Adolf Hitler's paintings, and a notebook that proves German officials were attempting to gain geo-political advantage by instigating communist revolution.
Coldcut produced an album with a song called Rubyaiyat on their album, Let us Play! This song contains what appears to be some words from the English translation. See album
In one 6-episode story of The Rocky and Bullwinkle Show, Bullwinkle finds the Ruby Yacht of Omar Khayyam in the town of Frostbite Falls (on the shores of Veronica Lake, no less).
In the play and film The Music Man, town librarian Marian Paroo draws down the wrath of the mayor's wife for encouraging the woman's daughter to read the Rubaiyat.
Referring to the Fitzgerald translation, the yogi Paramahansa Yogananda wrote an exegesis of the Rubaiyat exploring its mystical themes. This analysis and commentary was posthumously published in 1994 by the Self-Realization Fellowship under the title Wine of the Mystic: The Rubaiyat of Omar Khayyam, A Spiritual Interpretation (ISBN 0-87612-225-X).