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Ptolemaeus Arabus et Latinus

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Work B.2

Liber de compositione universalis astrolabii

A text on the construction of the universal astrolabe in six chapters. According to the colophon, it was translated from the Arabic in London in ‘era 1185’, i.e. in 1147 A.D., and three of the manuscripts name Robert of Chester (‘Robertus Cestrensis/Castrensis’) as the translator (MSS Cambridge, GCC, 35; Fermo, BC, 85; and Vienna, ÖNB, 5311). The text is unambiguously attributed to Ptolemy not only in the colophon, but also in the body of the text, where the author refers to the Almagest as his own work (‘librum meum Almagesti perlegat’, c. 6, Oxford, BL, Digby 40, f. 7r). However, Kunitzsch, 490, has shown that this work is not a translation, but a Latin compilation that draws upon previous works on the astrolabe. This, of course, does not disqualify Robert of Chester from being the author or compilator. Robert of Chester (‘Robertus Cestrensis’) is also credited with a text on the use of the astrolabe in 35 chapters extant in MS Oxford, BL, Canon. Misc. 61, f. 12r-22v (see), on which see Kunitzsch, 492 (also 506).

Note 1

Some sections of the old corpus on the astrolabe, put together from Arabic sources in Catalonia c. 1000, were already attributed to Ptolemy: see Horologium regis Ptolomei, or part C of the Sententie astrolabii, in 22 chapters (ed. J. M. Millàs Vallicrosa, Assaig d’història de les idees físiques i matemàtiques a la Catalunya medieval, Barcelona, 1931, 280-288); and Compositio astrolapsus secundum Ptolomeum, inc. ‘Iubet rex Ptolomeus bene politam fieri tabulam…’ (ed. ibid., 322-324). The Sententie astrolabii as a whole is attributed to Ptolemy in MS Sevilla, BCC, 5-2-16, s. XII, f. 1r-8r (‘Incipit liber de labore vel scientia astrolapsus et horologii interpretatus de Arabigo in Latinum a rege Tolomeo’). The De utilitatibus astrolabii is attributed to Ptolemy in five manuscripts (Avranches, BM, 235, s. XII, f. 58r: ‘Capitula Ptolomei de astrolabio’ and ‘Regulae Ptolomei super astrolabium’; London, BL, Addit. 17808, s. XI, f. 73v: ‘Regulae ex libris Ptolomei regis de compositione astrolapsus’; Los Angeles, J. Paul Getty Museum, Ludwig XII.5, s. XII, f. 101v-103r: ‘Incipit Spera Tholomei vel astralabium ipsius’; Paris, BM, 3642, s. XIII, f. 56vb: ‘Tractatus Tholomei de astrolapsu’; Paris, BnF, lat. 14065, s. XI-XII, f. 48v-51r: ‘Regulae ex libris Ptolomei regis de compositione astrolapsus’). According to Charles Burnett (‘King Ptolemy and Alchandreus the Philosopher: The Earliest Texts on the Astrolabe and Arabic Astrology at Fleury, Micy and Chartres’, Annals of Science 55 (1998), 329-368: 341), the attribution of these texts to Ptolemy would rather be ‘the responsibility of later redactors and scribes, and not to the original translator/compiler of the Latin texts from Arabic sources’.

Note 2

Two manuscripts of the old corpus on the astrolabe (Note 1) also contain a text ‘Liber de Wazalchora. Spera Ptolomei, quam astrolabium vel astrolapsum pocius Wazalcoram, id est planam speram, appellamus…’ (London, BL, Arundel 339, s. XII-XIII, f. 90r-97v; and Munich, BSB, Clm 15957, s. XII-XIII, f. 11r-32r). The incipit rather refers to an instrument invented or made by Ptolemy, not to a text composed by him. According to Kunitzsch, 493-494, this text is a Western compilation partly based on the Sententie astrolabii from the old corpus on the astrolabe.


‘(Oxford, BL, Digby 40) In nomine domini pii et misericordis incipit liber de compositione universalis astrolabii. [translator’s preface] Ptolomeus igitur, Mercurii incedens vestigiis in libro suo qui vocatur Almagesti, de motu sic ait: Ait enim omnis motus aut de puncto aut ad punctum — (1v) a docto artifice perpenditur. Explicit prologus. Incipit liber. [text] Sit igitur mater tabula, astrolabii videlicet generalis ex eramine rotundissime composita — cum una eademque utrique conveniat ad plenum dicetur. Explicit liber Ptolomei de compositione astrolabii universalis quem scilicet in civitate Londonie ex Arabico in Latinum transtulit, era millesima centesima LXXXV.’


C. H. Haskins, Studies in the History of Mediaeval Science, Cambridge, 1927 (2nd ed.), 122; F. J. Carmody, Arabic Astronomical and Astrological Sciences in Latin Translation. A Critical Bibliography, Berkeley-Los Angeles, 1956, 19 (no. 19, also nos. 14-18);  J. D. North, Richard of Wallingford: An Edition of His Writings with Introduction, English Translation and Commentary, Oxford, 1976, III, 162-164; P. Kunitzsch, Glossar der arabischen Fachausdrücke in der mittelalterlichen europäischen Astrolabliteratur, Göttingen, 1983 (Nachrichten der Akademie der Wissenschaften in Göttingen, I: Philologisch-Historische Klasse 11 (1982), 459-571), 489-491. For works on the astrolabe attributed to Ptolemy in Arabic (and Hebrew), see M. Steinschneider, Die hebraeischen Uebersetzungen des Mittelalters und die Juden als Doltmetscher. Ein Beitrag zur Literaturgeschichte des Mittelalters, Berlin, 1893, II, 536-538; F. Sezgin, Geschichte des arabischen Schrifttums, V: Mathematik, Leiden, 1974, 171-174 (nos. 2-3), and VI: Astronomie, Leiden, 1978, 95 (no. IV); and H. Y. Sheynin, ‘Claudius Ptolemy? Pseudo-Ptolemy? The Main Source of Moses Almosnimo’s Treatise on Astrolabe’, Journal for the History of Astronomy 46 (2015), 343-350.