Project icon: lavishly furnished initial letter with a painting of Ptolemy using an astrolab.

Ptolemaeus Arabus et Latinus

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Escorial, Real Biblioteca del Monasterio de San Lorenzo, O.II.10

s. XIIIex-XIVin.


northern France, perhaps Paris.


John of Murs, who heavily annotated the MS, at least from 1321 to 1344 (Gushee, 12); monastery of Poblet? (Antolín).

Parchment, 226 f., one or two neat hands copied the core of the MS, richly decorated initials.

Computus, arithmetic and astronomy: the original core of the MS includes Pseudo-Robert Grosseteste, Kalendarium (4r-10r); Tabula Gerlandi (10v-12rb); Balduinus de Mardochio or Marrochio, Compotus manualis (12rb-17v); Sacrobosco, Algorismus (19r-26r); Sacrobosco, De sphera (26v-39v); Sacrobosco, Computus (40r-63v); Robertus Anglicus, Quadrans vetus (64r-67v), with solar tables (68r-68v); Pseudo-Messahallah, De compositione astrolabii, beginning only (69r-71v); Theorica planetarum Gerardi (72r-79v); Pseudo-Thebit Bencora, De motu octave spere (80v-84r); Ptolemaica (84v-88r); Thebit Bencora, De recta imaginatione spere et circulorum eius diversorum (88v-90r); Thebit Bencora (?), De quantitate stellarum et planetarum et proportione terre (90r-92r); canons of Toledan tables (94r-123r); Toledan tables (124r-204r), including a selection of John of Ligneres’s canons, added by a 14th-c. hand (186r-189v); on eclipses ‘Ut annos Arabum et menses et per consequens…’, dated 1277 (205ra-217rb). Blank: 80r. John of Murs glossed most of the texts and added notes, tables and personal observations, mainly of an astronomical nature, on originally blank pages, f. 1-3, 18, 92v-93v, 123, 204v and 217v-226v.


G. Antolín, Catálogo de los códices latinos de la Real Biblioteca del Escorial, III, Madrid, 1913, 209-211; L. Gushee, ‘New Sources for the Biography of Johannes de Muris’, Jounal of the American Musicological Society 22 (1970), 3-26; G. Beaujouan, ‘Observations et calculs astronomiques de Jean de Murs (1321-1344)’, in Proceedings of the XIVth International Congress of the History of Science (Tokyo-Kyoto 1974), Tokyo, 1975, 27-30 (reprinted in G. Beaujouan, Par raison de nombres. L’art du calcul et les savoirs scientifiques médiévaux, Aldershot, 1991, VII); F. S. Pedersen, The Toledan Tables. A Review of the Manuscripts and the Textual Versions with an Edition, København, 2002, I, 114. M. Husson, ‘Exploring the Temporality of Complex Computational Practice: Two Eclipse Notes by John of Murs in the ms Escorial O II 10’, in How do Writings in the Early Astral Sciences Reveal Mathematical Practices and Practitioners?, eds M. Husson, R. L. Kremer, special issue of Centaurus 58 (2016), 46-65.


‘Thebit Bencorat de hiis que indigent expositione antequam legatur Al<magesti>. Equator diei est circulus maior qui describitur super 2 polos mundi — propinqui oppositioni Solis erunt, erunt retrogradi. Explicit Thebit de hiis que indigent expositione antequam legatur Almagesti et dicitur Equator diei.’

= Thebit Bencora, De hiis que indigent expositione antequam legatur Almagesti (C.1.1)

. No glosses. One marginal correction by the scribe f. 87r. Notes dated 1342 added by John of Murs after the explicit f. 88r.