The term dār al-ʿilm or dār lil-ʿilm (Ar. college; lit. house of knowledge) was applied to several Muslim libraries and scientific institutions in the eastern Islamic world in the ninth and tenth centuries. One of the most important was founded by the vizier Abū Naṣr Sābūr ibn Ardashīr in Baghdad during the reign of Bahāʾ al-Dawla (991–993). According to the fifteenth-century chronicler Ibn al-Hītī, the Karaite place of learning in Jerusalem in the first half of the eleventh century was also known as a dār lil-ʿilm. Ibn al-Hītī states that the school belonged to Abū Yaʿqūb Yūsuf ibn Nūḥ, who…