Ptolemy in the Renaissance

Abstract

Among the works written by, or attributed to, Claudius Ptolemy (ca. AD 100 -ca. 170), those which enjoyed the warmest reception in the Renaissance were: [1] the Almagest; [2] De Analemmate; [3] Planetary Hypotheses; [4] Quadripartitum and the (spurious) Centiloquium; [5] Geography; [6] Planisphaerium; [7] Optics; [8] Harmonics; and later [9] Phaseis and [10] On the Criterion (of Truth) and the Commanding-Faculty with the Canobic Inscription. Impact and legacyAmong the works written by, or attributed to, Claudius Ptolemy (ca. AD 100 -ca. 170), those which enjoyed the warmest reception in the Renaissance were: [1] the Almagest; [2] De Analemmate; [3] Planetary Hypotheses; [4] Quadripartitum and the (spurious) Centiloquium; [5] Geography; [6] Planisphaerium; [7] Optics; [8] Harmonics; and, later, [9] Phaseis, and [10] On the Criterion and the Commanding-Faculty, with the Canobic Inscription.[1] Ptolemy's resurgence in the Renaissance had a deep and extensive impact on astronomy and cosmology. His Almagest (Μεγίστη Μαθηματικὴ Σύνταξις) regained an unparalleled centrality in these fields between the mid-15th and the mid-16th century. At first, the Almagest was studied in small circles of specialists, who soon became aware of the unreliability of Gerard of Cremona's translation from the Arabic (Toledo, 1175). So, between the 1420s and the 1440s, scholars began to (re)study Ptolemy on the basis of the original text preserved in Constantinople: John Chortasmenos left a lot of notes and calculations in his copy of the Almagest; Bessarion handcopied the Commentary by John Alexandrinus; and Gemistus Pletho studied the one by Theodore Metochites (cf. Rigo 1991). The intrinsic complexity of the text and the mathematics within it were made more accessible to students on various occasions: for instance, the anonymous Almagestum Parvum offered an abridged formulation of Ptolemaic astronomy in the style of Euclid's Elements (Zepeda 2015), while Giovanni Bianchini's Flores Almagesti (1446-1456), following Ptolemy's footsteps, disclosed innovative methods for the computation of stellar coordinates and mathematical astronomy in general (Van Brummelen 2018). In the West, however, such a rediscovery begun precisely in 1451, when Pope Nicholas V commissioned George of Trebizond to produce a Latin translation of the Almagest based on a Greek manuscript from Bessarion's library. The Cretan scholar completed the requested translation by the end of that year; he also completed and attached his demanding commentary on that work, in which he extensively criticized the historic Commentary by Theon of Alexandria, in an effort to restore Ptolemy's original text by dispelling subsequent misunderstandings. Even though George of Trebizond tried to gain recognition and to promote his work in Venice, Rome, Naples, Istanbul, and Budapest, his anti-Theonian Commentary became the target of a harsh polemical campaign fuelled by Cardinal Bessarion (Steiris 2010). The latter first exploited the negative evaluation of George's endeavor by the papal reviewe...