The existing variations in the basic accounts of al-Farabi's origins and pedigree indicate that they were not recorded during his lifetime or soon thereafter by anyone with concrete information, but were based on hearsay or guesses (as is the case with other contemporaries of al-Farabi). Little is known about his life. Early sources include an autobiographical passage where al-Farabi traces the history of logic and philosophy up to his time, and brief mentions by al-Masudi, Ibn al-Nadim and Ibn Hawqal. Said al-Andalusi wrote a biography of al-Farabi. Arabic biographers of the 12th–13th centuries thus had few facts to hand, and used invented stories about his life.