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Ptolemaeus Arabus et Latinus

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Work C.1.23

Defensio Theonis contra Trapezuntium


‘(St Petersburg, BAN, IV-1-935, ed. Shank/Kremer) [preface] Nuper quosdam offendi commentarios in magnam Claudii Ptolemaei compositionem inclito ac Christianissimo Pannoniarum regi Matthiae autore Georgio Trapezuntio inscriptos, quorum ingenti magnitudine subitaque novitate mirum in modum letabar, talis iamdiu cupieris expectans muneris, multo autem maximum videndi desiderium ardorem instinxit maiestas principis cui opus illud dedicatum erat. Non enim nisi elegantissimo quolibet atque optimo — ab iniuriis distat abstinere siquando alieno indire peccata sua recognoverit. [title] Defensio Theonis contra Trapezuntium. [chapter 1] In prefatione Leonem Judeum carpens inquit: Nec potuit percipere dispositiones aeris propinquitatem et remotionem in visu plurimum immutare. Propinquiora enim apparent que humido crassoque medio cernimus — clientulo indicatam tuo declinare velis. Hinc procul fugite quicumque sideralem queritis disciplinam commentariosque mendaces una cum autore suo Georgio Trapezuntio sinite valere.’


A sharp criticism of George of Trebizond’s commentary on the Almagest (C.1.19). The editors have divided the work into 13 chapters following the 13 books of the Almagest.


This work survives mainly in MS St Petersburg, BAN, IV-1-935, which appears to be the draft of the text, with numerous corrections, copied by Regiomontanus himself, probably between c. 1462 and c. 1475.


E. Zinner, Regiomontanus: His Life and Work, Amsterdam-New York-Oxford-Tokyo, 1990 (tr. with additions of Leben und Wirken des Joh. Müller von Köningsberg, genannt Regiomontanus, Osnabrück, 1968), 97-98; M. Shank, ‘Regiomontanus and Homocentric Astronomy’, Journal for the History of Astronomy 29 (1998), 157-166: 161-163; M. Shank, ‘Regiomontanus on Ptolemy, Physical Orbs, and Astronomical Fictionalism: Goldsteinian Themes in the “Defense of Theon against George of Trebizond”’, Perspectives on Science 10 (2002), 179-207; M. Shank, ‘Regiomontanus as A Physical Astronomer: Samplings from The Defence of Theon against George of Trebizond’, Journal for the History of Astronomy 38 (2007), 325-349; M. Malpangotto, Regiomontano e il rinnovamento del sapere matematico e astronomico nel Quattrocento, Bari, 2008, 45-48; H. Zepeda, The Medieval Latin Transmission of the Menelaus Theorem, PhD Dissertation, University of Oklahoma at Norman, 2013, 339; M. Shank, ‘Regiomontanus and Astronomical Controversy in the Background of Copernicus’ in Before Copernicus. The Culture and Contexts of Scientific Learning in the Fifteenth Century, eds R. Feldhay, F. J. Ragep, Montreal-London-Chicago, 2017, 79-109: 94-96; M. Shank, ‘Regiomontanus versus George of Trebizond on Planetary Order, Distances, and Orbs (Almagest 9.1)’, in Ptolemy’s Science of the Stars in the Middle Ages, eds D. Juste, B. van Dalen, D. N. Hasse, C. Burnett, Turnhout, 2020, 305-386.


Online facsimile of MS St Petersburg, BAN, IV-1-935, with diplomatic edition, introduction and notes by M. Shank and R. L. Kremer at (2009).