Abharī, sometimes referred to as “Athīr al-Dīn al-Munajjim” (the astrologer), was a philosopher who wrote on logic, mathematics, and astronomy. It is speculated that Abharī was born in Mosul; “Samarqandī” in his name indicates that either he or his ancestors originally stemmed from there, most likely belonging to the Abhar tribe. It is believed that he attended primary school in Mosul, and then traveled to Khurāsān, Baghdad, and Arbil to continue his studies. Ibn Khallikān reportsthat he took part in the assemblies of the famous scholar Kamāl al-Dīn ibn Yūnus (d. 1242) and worked as his assistant at the Badriyya School in Mosul. Other reports claim that Abharī was a student of Fakhr al-Dīn al-Rāzī (d. 1210), that he taught at the Sharafiyya School in 1248 in Baghdad, that he traveled to Iran from Mosul, that he lived for a time in Sivas in Anatolia, and that he eventually died of paralysis in Azerbaijan. Abharī dealt with astronomy in several of his works: he devoted the second part of the third chapter of his work, Kashf al-ḥaqā’iq fī taḥrīr al-daqā’iq, to astronomy; his independent astronomical works include treatises on the astrolabe, commentaries on earlier zījes, and compendia on astronomy. In the latter category, we find a Risāla fī al-hay’a (Treatise on astronomy; extant in Istanbul, Süleymaniye, H. Hüsnü MS 1135) and a Mukhtaṣar fī al-hay’a (Epitome of astronomy, extant in Istanbul, Süleymaniye, Carullah MS 1499). Abharī wrote several mathematical works, including a “Correction” (Iṣlāḥ) of Euclid. Among the “corrections” is an attempt to prove the Parallels Postulate. This was quoted in later works, in particular by Samarqandī, who was critical of Abharī’s proof. [H. Sarıoğlu]; GAS V.111