Firdausi or Firdusi, the pseudonym of Abu-'l Kasim Mansur, the great poet of Persia, born near Tûs, in Khorassan; flourished in the 10th century B.C.; spent 30 years in writing the "Shah Nama," a national epic, but having been cheated out of the reward promised by Sultan Mahmud, he gave vent to bitter satire against his royal master and fled the court; for some time he led a wandering life, till at length he returned to his birthplace, where he died; a complete translation of his great poem exists in French.