"Rubaiyat of Omar Khayyam" is the title that Edward Fitz Gerald gave to his translation of a selection of poems, originally written in Persian and numbering about a thousand, attributed to Omar Khayyam (1048-1131), a Persian poet, mathematician and astronomer. A ‘ruba’i’ is a two-line stanza with two parts per line, hence the word rubaiyat (derived from the Arabic language root for "four"), meaning "quatrains". As a work of eng literature Fitz Gerald’s version is a high point of the 19th century and has been greatly influential. Indeed, the term "Rubaiyat" by itself has come to be used to describe the quatrain rhyme scheme that Fitz Gerald used in his translations: AABA. (Excerpt from Wikipedia)