An Arabic translation of al-Ṭūsī’s Persian commentary on the Thamara (C.3.1250), with the Arabic base text transcribed directly from al-Ṭūsī’s source text. Although anonymous in the manuscripts, the translation is most likely the one authored by Rukn al-Dīn Muḥammad b. ʿAlī b. Muḥammad al-Jurjānī (fl. c. 697-728/1297-1327), which is known through a reference in a further Ṭūsī translation of his (ed. Mudarrisī, p. 24 lines 6-9; cf. Murawwaj, Lameer) and has hitherto been considered lost. Only the late manuscript Tehran, Millī Library, 7450 may transmit a translation different from Rukn al-Dīn’s, or alternatively a draft or a reworking thereof, as can be seen from its less elegant wording and some differences in the content: as opposed to the other Arabic witnesses, the ceremonious opening section starting with yaqūlu mawlānā is omitted while the commentator’s introduction is not.