The House of Wisdom (Arabic: بَيْت الْحِكْمَة Bayt al-Ḥikmah), also known as the Grand Library of Baghdad, was believed to be a major Abbasid-era public academy and intellectual center in Baghdad. In popular reference, it acted as one of the world's largest public libraries during the Islamic Golden Age, and was founded either as a library for the collections of the fifth Abbasid caliph Harun al-Rashid (r. 786–809) in the late 8th century or as a private collection of the second Abbasid caliph al-Mansur (r. 754–775) to house rare books and collections in the Arabic language. During the reign of the seventh Abbasid caliph al-Ma'mun (r. 813 – 833 AD), it was turned into a public academy and a library.
It was destroyed in 1258 during the Mongol siege of Baghdad. The primary sources behind the House of Wisdom narrative date between the late eight centuries and thirteenth centuries, and most importantly include the references in Ibn al-Nadim's (d. 995) al-Fihrist.