〈Gebri Hispalensis reprehensiones et correctiones in Ptolemei Magna compositione〉
This list of 22 criticisms and corrections to the Almagest by Geber (see C.1.2) in Averroes’s rendering was copied by George of Trebizond in his personal notebook, which also contains the first draft of his commentary on the Almagest (C.1.19). Averroes criticised Ptolemy in several of his works, in particular in his Epitome of the Almagest (Mukhtaṣar al-Majistī, 1159-1162), which survives only in a Hebrew translation made by Jacob Anatoli in Naples in 1231 and of which eleven manuscripts are known. The present list of 22 criticisms and corrections by Geber is not found in Averroes’s Epitome, but Lay suggests that George of Trebizond may have derived it from the commentary on the Epitome by Efodi (Profiat Duran, c. 1340-1415), extant in MS Paris, BnF, hébreu 1021, f. 29r-31r, immediately after the text of the Epitome.
‘(Torino, BNU, G II 36) Averois: Volo ponere ea in quibus reprehendit Geber Hispalen<sis> Ptolemeum in Magna compositione et correxit, sicut putavit, demonstrationibus suis. Primum in libro primo quod Ptolemeus ex figura sectoris fieri demonstravit per sex lineas — ponit eius super Solem.’
J. Monfasani, Collectanea Trapezuntiana: Texts, Documents, and Bibliographies of George of Trebizond, Binghamton (NY), 1984, 677-678; J. Lay, ‘L’abrégé de l’Almageste. Un inédit d’Averroès en version hébraïque’, Arabic Sciences and Philosophy 6 (1996), 23-61: 33. On Averroes’s Epitome of the Almagest, see also M. Steinschneider, Die hebraeischen Uebersetzungen des Mittelalters und die Juden als Dolmetscher, Berlin, 1893, II, 546-549; R. Lorch, ‘The Astronomy of Jābir b. Aflāḥ’, Centaurus 19 (1975), 85-107: 99-100 (reprinted in R. Lorch, Arabic Mathematical Sciences. Instruments, Texts, Transmission, Farnham-Burlington, 1995, VI); D. N. Hasse, ‘Averroes’ Critique of Ptolemy and Its Reception by John of Jandun and Agostino Nifo’, in Averroes’ Natural Philosophy and Its Reception in the Latin West, ed. J. J. M. Bakker, Leuven, 2015, 69-88: 72-73.