The term 'RUBAIYAT POET' refers to the Persian poet Omar Khayyam, who is best known for his collection of quatrains called the Rubaiyat. Omar was born in 1048 in Nishapur, Iran and was a mathematician, astronomer, and philosopher in addition to being a poet. He is considered one of the most influential figures in Persian literature. The four-letter answer to the crossword puzzle is OMAR, which is the poet's given name. The eleven-letter answer is OMARKHAYYAM, which is his full name.