Ahmad ibn Muhammad ibn al-Sari Ibn al-Salah

Najm al-Dīn Abū al-Futūḥ Aḥmad ibn Muḥammad ibn al-Sarī, called Ibn al-Ṣalāḥ (died 1154), was a scholar who wrote critical commentaries on logic and mathematics. In total at least 17 works by Ibn al-Ṣalāh are extant today.^[1]

Ibn al-Ṣalāḥ was born either at Samsat or Hamadan. He trained as a physician.^[2] He served as court physician to Ilghazi (r. 1107–1122), the Artuqid ruler of Mardin.^[3] He ended his life in Damascus. He is known for his critique of errors in the transmission of Ptolemy's Almagest, for which he examined one Syriac and four Arabic manuscripts.^[2] He wrote a Treatise on Projection, commentaries on Galen and eight tracts on Euclid's Elements.^[3]