Al-Maghāriyya (The Cave Sect) is mentioned by the Karaite scholars Jacob al-Qirqisānī and Judah Hadassi, as well as by the Muslim writers al-Bīrūnī and al-Shahrastānī, deriving in part from works by Severus ibn al-Muqaffaʿ, David ibn Marwān al-Muqammiṣ, and Abū ʿĪsa al-Warrāq. Stroumsa observes that David ibn Marwān al-Muqammiṣ was interested in the sect in connection with Christian origins. However, the historical evidence for the al-Maghāriyya as an ancient sect is slim, consisting solely of al-Shahrastānī’s claim that they lived four hundred years before Arius (ca. …