From Arabic, lit. ‘Brethren of Purity’, a group of learned scholars who were based in Basra and Baghdad around the last quarter of the tenth century CE. It is more generally accepted that their line in literature belonged to the Shi‘a legacy with strong connections with the Ismaili tradition. The Ikhwan produced an encyclopaedic work of 52 volumes Rasa’il Ikhwan al-Safa’ (The Epistles of the Brethren of Purity). These embodied the scientific and philosophical knowledge of their time. The Epistles treated a wide array of subjects including astronomy, logic, math, music, and natural sciences. Besides, the Epistles also explored the nature of the soul and investigated associated matters in ethics, revelation, and spirituality.