In mathematics he contributed to the theory of equations, to the understanding of the parallel axiom, and possibly to the generalization of the binomial theorem. As an astronomer he contributed to a calendar reform when Sultan Malik-Shah decided that the calendar needed some adjusting. He is best known for his agnostic and sceptic poetry, largely because of the publication in 1859 of "Rubaiyat of Omar Khayyam" by the translator Edward Fitzgerald.