Seljuq dynasty
Omar Khayyam was born in 1048 in Nishapur, a leading metropolis in Khorasan during medieval times that reached its zenith of prosperity in the eleventh century under the Seljuq dynasty. Nishapur was also a major center of the Zoroastrian religion, and it is likely that Khayyam's father was a Zoroastrian who had converted to Islam. His full name, as it appears in the Arabic sources, was "Abu’l Fath Omar ibn Ibrahim al-Khayyam".