John of Pulchro Rivo and John of Saxony: A Mise au Point

Alfontii regis castelle illustrissimi celestium motuum tabule (Venice, 1483). This incunabulum was the basis for the edition in E. Poulle, Les Tables Alphonsines avec les canons de Jean de Saxe (Paris, 1984). An English translation of the canons is included in E. Grant, A source book in medieval science (Cambridge, MA, 1974), 456–87. On John of Saxony and the Alfonsine Tables, see further R. L. Kremer, “Thoughts on John of Saxony's method for finding times of true syzygy”, Historia mathematica, xxx (2003), 263–77; J. Chabás and B. R. Goldstein, The Alfonsine Tables of Toledo (Dordrecht, 2003), 284–9.

See, e.g., MS Cambridge, University Library, Mm. iii. 11, fol. 51r: “… secundum doctrinam magistri Johannis de Lineriis, a quo habeo scientiam meam.” The eclipse canons are also included in the 1483 editio princeps of the Alfonsine Tables, albeit without the crucial passage. See J. L. E. Dreyer, “On the original form of the Alfonsine Tables”, Monthly notices of the Royal Astronomical Society, lxxx (1920), 243–62, p. 252; E. Poulle, “Les astronomes parisiens au XIV^e siècle et l'astronomie alphonsine”, in Histoire littéraire de la France, xliii/1 (Paris, 2005), 1–54, p. 50.

Poulle E. , “John of Lignères”, in Dictionary of scientific biography, vii, 122-8.

MS Erfurt, UB, Ampl. 2° 377, fol. 35r: “Expliciunt canones tabularum astronomie ordinati per magistrum Iohannem Pychardum de Lyneriis et completi Parisius anno ab incarnatione Christi filii Dei 1322, scripte Parisius per manum Iohannis de Danecowe Anno Domini M°CCC°XXIII° in die cathedra Petri.” See Schum W. , Beschreibendes Verzeichnis der amplonianischen Handschriften-Sammlung zu Erfurt (Berlin, 1887), 262–4.

On John of Saxony's oeuvre, see Poulle E. , “John of Saxony”, in Dictionary of scientific biography, vii, 139-41; Poulle, “Les astronomes” (ref. 2), 45–53; O. Weijers, Le travail intellectuel à la Faculté des Arts de Paris: Textes et maîtres (ca. 1200–1500) (Turnhout, 1994–2012), v, 161–3.

MS Florence Plut 30.24, fols. 78r-86r (text), 87r-96v (commentary). The incipits and explicits in this MS are as follows: “Incipit compotus novus magistri Iohannis de Saxonia qui distinguitur per 18 capitula” (fol. 78ra). “Explicit compotus novus magistri Iohannis de Saxonia” (fol. 86rb). “Incipiunt scripta super novum compotum magistri Iohannis de Saxonia” (fol. 87ra). “Explicit scriptum super novum compotum magistri Iohannis de Saxonia compositum ab eodem Iohannem Anno Domini 1297” (fol. 99rb).

MS Erfurt, UB, Ampl. 4° 365, fol. 139r: “Expliciunt notule supra compotum magistri Iohannis de Saxonia, extracte a scriptis eiusdem completis Anno Domini 1297.” Schum, Verzeichnis (ref. 4), 611.

Duhem P. , Le système du monde (Paris, 1913–59), iv, 77.

Le recueil des plus célèbres astrologues de Simon de Phares, ed. by Boudet J.-P. (Paris, 1997–99), i, 474; L. Thorndike, A history of magic and experimental science (New York, 1923–58), iii, 255–6. See also J.-P. Boudet, Lire dans le ciel: La bibliothèque de Simon de Phares astrologue du XVe siècle (Brussels, 1994), 186–7.

Thorndike , A history (ref. 9), iii, 254 n2: “It would seem either that there is some mistake in the date 1297, or that the treatise on computus should not be ascribed to John Danko of Saxony, the disciple of John de Lineriis.”

Poulle , “John of Saxony” (ref. 5), 140–1.

Poulle , “Les astronomes” (ref. 2), 45–52.

Boncompagni B. , “Intorno ad un tratatto d'arithmetica stampato nel 1478”, Atti dell'Accademia Pontificia de’ Nuovi Lincei, xvi (1862–63), 1–64, 101–228, 301–64, 389–452, 503–630, 683–842, 909–1044.

Swetz F. J. , Capitalism and arithmetic (La Salle, IL, 1987), 165–8.

Boncompagni , “Intorno ad un tratatto” (ref. 13), 689–94, 711–32. MS Glasgow, UL, Hunter 444, p. 18: “Incipit compotus novus editus a Iohanne de Saxonia.” MS Leiden, UB, Scaliger 66, ol. 9ra: “Incipit novus compotus Iohannis de sacsonia quem compilavit ex valde multis compotis.”

See Colophons de manuscrits occidentaux des origines au XVIe siècle (Fribourg, 1965–82), vi, 468 (no. 23175), and MSS Glasgow, UL, Hunter 444, p. 47; Leiden, UB, Scaliger 66, fol. 37v. The year 1297 is also mentioned elsewhere in the text. See ibid., fol. 10vb: “Ignorans vero chifram istud preaccipiat tamquam notum quod anno gratie 1297 fuerit primus annus huius cicli, 10mus indictionis, aurei vero numeri 6, ut inferius apparebit. Unde versus: ‘Anno milleno trecenteno tria demo. Dat decas indictio, 6 aureus, sol dabit unum’.” Ibid., fol. 19vb-20ra: “Sed ab incarnatione domini sunt elapsi 1297 anni.” The Florentine MS has 1397 instead of 1297 in certain places, but this is an obvious scribal error, perhaps motivated by the fact that the manuscript was written close to this year.

MS Vat. lat. 3112, fol. 67va: “Explicit Anno Domini 1298 die Martis post ramos palmarum kl. Aprilis. Explicit sententia compoti nove compilationis.” The explicits of the commentary in MSS Florence Plut. 30.24, fol. 99rb (ref. 6) and Erfurt, UB, Ampl. 4° 365, fol. 139r (ref. 7) mention the year 1297, but this was probably just derived from the date in the main text.

MS Florence Plut. 30.24, fol. 78r: “Omissis preternecessariis cum intentionis sit in hoc epylogo compendium emendare, utinam ad unguem, nuper minus deliberatum a nobis ob importunas precum instantias ad omne datum tempus sine cyfra compilatum perutile videbatur addere omnia secundum propositum utiliora que declivitas ingenii freta Dei auxilio pro posse suppetivit colligere modo lucido compendioso et moderno de phylosophicis voluminibus Dyonisii, Bede, Hilperici, Gerlandi, Herimani, Ydioth, Ymaginis mundi, Compoti ecclesiastici, Masse compoti, Johannis de Sacrobosco, Lyconiensis, Campani, Metri ecclesie, Baldeuini, Ferrandi, Compoti phylosophici, Compoti manualis, Iohannis de Meldis, Thome de Auge, et quam plurium aliorum.” Other authorities cited in the course of the text and its commentary include Plato, Aristotle, Hippocrates, Galen, Ptolemy, Macrobius, Boethius, Iohannes Hispalensis, al-Battānī, al-Farghānī, al-Qabīsī, Thābit, Haly, Azarquiel, ‘frater Egidius’, ‘liber Nemroth’, Albert the Great, and Peter of Dacia.

MS Vat. lat. 3112, fol. 29vb: “Et quoniam libri istorum fuerunt multi et diversi et quidam obscuri satis et prolixi, et quidam continentes antiqua dicta modicum valentia, et quidam diminuti, ideo ego Iohannes Alemannus hanc compilationem ad utilitatem omnium in quam potui melius compilavi. Et licet illa que ponuntur in hac compilatione satis sint lucida, ut patet intuenti litteram, nihilominus, quia plures intelligentes me rogaverunt ut eis aliquam sentenciam, scilicet dictionem, in generali compilarem … hanc compilationem seu dictionem in quodam communi sum aggressus, Dei gratia cooperante.”

Ibid., fol. 30rb-va: “Unde notandum quod auctor iste quoddam aliud compendium absque omni cifra ad omne tempus interrogatum compilavit propter petitionem quorundam amicorum suorum et hoc sine magna deliberatione, quod incipit sic: ‘Ad habendum ciclum solarem secundum Gerlandum’.”

Ibid., fol. 32vb: “‘Ut docet manus’: id est compotus manualis quem compilavit Io. Alemannus de Pulcro Rivo, qui minus subtilis est quoad manum.” MS Florence Plut. 30.24, fol. 88va, has compilavis for compilavit and magis for minus.

In his commentary, John generally speaks of himself as the ‘auctor’ in the third person. Note that the commentary in MS Vat. lat. 3112, fol. 31vb-32r, contains three references to a tabula Iohannis Alemanni, which the text in MS Florence Plut. 30.24, fol. 88r, changes to tabula mea. See also ref. 47 below and Boncompagni, “Intorno ad un trattato” (ref. 13), 722–3.

A list of all copies known to me is provided in section A of the Appendix above. See further Thorndike L. and Kibre P. , A catalogue of incipits of mediaeval scientific writings in Latin, rev. edn (London, 1963), col. 41; B. Hauréau, Initia operum scriptorum latinorum medii potissimum aevi (Turnhout, 1973–74), i, fol. 28vb; R. Aubert, “Jean de Pulchro Rivo”, in Dictionnaire d'histoire et de géographie ecclésiastiques (Paris, 1912-), xxvii, col. 482; P. Glorieux, La Faculté des Arts et ses maîtres au XIIIe siècle (Paris, 1971), 233; A. Cordoliani, “Los manuscritos de cómputo eclesiástico en las bibliotecas de Barcelona”, Analecta Sacra Tarraconensia, xxiii (1950), 103–30, pp. 9–10, 18–19, 23; Cordoliani, “Inventaire des manuscrits de comput ecclésiastique conservés dans les bibliothèques de Catalogne”, Hispania sacra, iv (1951), 359–84, pp. 369–70; Cordoliani, “Les manuscrits de comput des bibliothèques d'Utrecht”, Scriptorium, xv (1961), 76–85, pp. 82–3; H.-W. Gümpel and K.-J. Sachs, “Das Manuskript Girona 91 und sein Contrapunctus-Traktat”, Archiv für Musikwissenschaft, xlv (1988), 186–205, pp. 187–8; R. Comes Maymó, “Textos llatins universitaris de l'Europa medieval en el Manuscrit 39 de la Biblioteca de Catalunya”, Anuari de Filologia, Secció D, xii (2003–4), 119–39, pp. 131–2, 136.

See, e.g., MS Paris, BnF, lat. 7420A, fol. 46vb: “Explicit elucidans compendium compotum manualem magistri Iohannis de Pulcro Rivo.” The ascription to John of Garland (Iohannes de Garlandia) found in some catalogues is due to a confusion with the eleventh-century computist Gerland, whose name is referenced in the initial line. See, e.g., H. Hagen (ed.), Catalogus codicum Bernensium (Bibliotheca Bongarsiana) (Bern, 1875), 411; Schum, Verzeichnis (ref. 4), 745, 777; O. Odenius, “Cisiojani Latini: Neue Beiträge zur Bibliographie der metrischen Kalendarien des Mittelalters”, Arv, xv (1959), 61–154, pp. 63–4, 78. Gerland's influential computus treatise, which originated the specific version of the solar cycle referred to by John of Pulchro Rivo, was recently edited by A. Lohr, Der Computus Gerlandi: Edition, Übersetzung, und Erläuterungen (Stuttgart, 2013).

See, e.g., MS Leiden, UB, Scaliger 66, fol. 1vb: “Notandum etiam quod istud fuit collectum Anno Domini 1289° et tunc habuimus 21 pro ciclo solari, pro aureo numero 17, et 2 pro indictionibus, de quibus duobus post ea dicetur.” In MS Bruges, Bibliothèque Municipale, 528, fol. 17v, the passage is updated to 1333.

Zinner E. , Verzeichnis der astronomischen Handschriften des deutschen Kulturgebietes (Munich, 1925), nos. 8810–15. See further Thorndike and Kibre, A catalogue (ref. 23), cols 764–5; Cordoliani, “Les manuscrits” (ref. 23), 82.

To judge from the reckoning examples in MSS London, BL, Royal 8. D. XIV, fol. 5ra, and Paris, BnF, lat. 7421, fol. 60v. Further MSS are listed in section C of the Appendix above.

MS Leiden, UB, Scaliger 66, fol. 7r: “Et hec de utilioribus que considerat compotista Parisius inchoata Anno Domini 1289°, Brunsvich consummata, ad instancias quorundam meorum specialium amicorum quantum declivitas mei ingenioli colligere suppetebat. Et hec dixisse sufficiant a me.” The same colophon, with a slightly different ending, is found in MS Erfurt, UB, Ampl. 12° 19, fol. 115r: “… ad instancias proborum virorum et meorum amicorum quantum declivitas mei ingenioli suppetebat anno presenti pro radice habito ad presens sufficiant compilata.” See also MS Utrecht, UB, IV.G.18 (722), fol. 73r.

See Boncompagni , “Intorno ad un tratatto” (ref. 13), 729–30, 787–8. I have dealt with this text in some depth in Appendix I of C. P. E. Nothaft, Medieval Latin Christian texts on the Jewish calendar (Leiden, 2014).

MS Lüneburg, Ratsbücherei, Miscell. D 4° 46, fol. 1ra: “Incipit conpotus philosophicus compositus per fratrem Iohannem ordinis fratrum minorum.” Ibid., fol. 18vb: “Explicit conpotus novus philosophicus compositus per fratrem Iohannem de G(u). …” In MS Vienna, ÖNB, 5239, fol. 28r, whose scribe used the Lüneburg copy as his exemplar, this is altered to what looks like Iohannes de S. Further MSS are listed in section C of the Appendix above.

For the ‘Toledan’ syzygy tables, see Toomer G. J. , “A survey of the Toledan Tables”, Osiris, xv (1968), 5–174, pp. 79–81; F. S. Pedersen, The Toledan Tables (Copenhagen, 2002), iv, 1327–40.

MS Hannover, NLB, IV 389, fol. 1va: “Anno Domini 1273 fundata est hec scientia super positionem Ptolomei. …” Ibid., fol. 1vb: “Anno Domini 1272, anno bisextili, 19 kalendas Ianuarii in meridie inveniebatur sol in principio Capricorni.” Ibid., fol. 2vb: “Anno Domini 1273 … fuit media coniunctio lune paschalis feria secunda post horas 6 partes 27.” Ibid., fol. 4va-b: “Anno enim Domini 1273, anno post bisextum, pridie ydus Martii in meridie sol pertransisse inveniebatur de primo gradu Arietis 40 minuta.” In contrast to the other known copies, the cited MS from Hannover (fols. 12v and 13v) omits the first three lines of anni collecti from the syzygy and trepidation tables of the second part, which are here moved to the very end of the text. They thus only start with the year 1330, which marks the beginning of the 19-year cycle in which the manuscript was copied. Its colophon reads: “Finitus est liber iste qui vocatur Compotus philosophicus Anno Domini 1342 18. die Martii” (fol. 12v).

The following tables with starting points in 1273 reappear in the Compotus novus: MS Hannover, NLB, IV 389 (H), fol. 5r (“Tabula coniunctionis et oppositionis medie fundate super quantitatem Arzachelis et Iudeorum”) = MS Leiden, UB, Scaliger 66 (L), fols. 22v, 23v; H, fol. 5v (“Tabula proprior ad inveniendum principia mensium Iudeorum”) = L, fol. 25r; H, fol. 9r (“Tabula ad inveniendum tempus Arabum per annos Cristi”) = L, fol. 26r.

MS Hannover, NLB, IV 389, fol. 10rb: “Sed si ad alteram civitatem, que est in occidente respectu Iherusalem, sicut est fere tota occidentalis ecclesia, volueris habere tempus medie coniunctionis vel oppositionis, vide eius differentiam ad Iherusalem in eclipsi et illam subtrahe a tempore coniunctionis vel oppositionis civitatis sancte ibi invento. Si autem ad Toletum habere volueris ipsum, subtrahe 3 horas et 27 minuta. Et si ad civitatem Magdeburg, que est in Almania [!], habere volueris tempus medie coniunctionis vel oppositionis, subtrahe 2 horas et 40 minuta a tempore secundum longitudinem civitatis sancte in tabulis invento.” ‘Toledan’ syzygy tables for mean conjunction normally have a starting date corresponding to 12 August a.d. 622, 22h 23m (see ref. 31), whereas the conjunction (molad) predicted by the Jewish calendar for the month of Elul that year fell on the same day at 19h + 905 halakim (from sunset) = 1h 50m (from noon). The difference is 3h 27m, exactly as stated in the text.

Magdeburg also makes an appearance in the second half of the Compotus philosophicus, where it is used as the locality of reference for a set of tables for the oblique ascension, its latitude being very accurately stated as 52°. MS Vat. lat. 3112, fol. 21vb: “Notandum est etiam quod ascensiones et partes hore circuli obliqui in tabulis posite fundate sunt super latitudinem 52 graduum, cuiusmodi est Magdeburg, quod est in Teutonia.”

MS Glasgow, UL, Hunter 444, pp. 41b-42a: “Cum hoc notandum est quod tempus medie coniunctionis hic positum est secundum longitudinem citivatis Iherusalem, quia Compotus philosophicus secutus est magistros Iudeorum, qui respectu huius civitatis posuerunt. Et quamvis Iudei sic ubique habeant, nihilominus, si ad civitatem Magdeburch, que est in Almannia, habere volueris subtrahe 2 horas et 40 [Ms.: 4] minuta a tempore civitatis Iherusalem iam predicto. Si autem ad villam Parisiensis volueris, 15 minuta subtrahe et 3 horas.”

MS Vatican City, BAV, lat. 3112, fol. 59vb: “Ulterius nota quod docet hic adequare ad civitatem Megdeburg in Almannia, quia Megdeburg est metropolis et ideo magis famosa, et non ad Bruneswic, de qua sum natus, neque ad civitatem Goslarie, in qua librum pro maiori parte compilavi.” The wording is slightly different in MS Florence Plut. 30.24, fol. 96vb: “Ulterius nota quod doceo hic adequare ad civitatem Magdebrach in Alemannia et non ad Bruneswich, de qua sum natus, quia Magdebrach est metropolis et ideo magis famosa, neque ad civitatem Goslarie in qua librum pro maiori parte compilavi.” The switch to the first-person form (‘doceo hic’) might suggest that John of Pulchro Rivo was himself the author of the Compotus philosophicus, but other considerations speak against this. The matter is discussed further in Appendix I of Nothaft, Medieval Latin Christian texts (ref. 29).

Poulle , “John of Saxony” (ref. 5), 140–1. The eclipse canons in MS Kraków, Biblioteka Jagiellońska, 613, fol. 176r (s. XIV ex.) ascribe the work to “Johannes Danikonis Magdeburgensis”, while MS Berlin, SBPK, 2° 246, fol. 121r (s. XV med.) finishes John's canons for the Alfonsine Tables with the note “istos canones composuit magister Johannes de Saxonia, alio nomine magister Johannes Danekow de Magdeborth”.

Poulle , “Les astronomes parisiens” (ref. 2), 49, mentions the passage but fails to notice how it contradicts his position. Based on the Florentine MS, he reads Gesmarie for Goslarie, which he takes to be Geismar in Thuringia, a small village of no significance in the thirteenth century. If anything, a more promising candidate would have been Geismar in Lower Saxony, which today is a part of Göttingen, but the reading of Goslarie, confirmed by the Vatican MS, is clearly the preferred one. The information contained in this passage also speaks against Moritz Steinschneider's conjecture that de Pulchro Rivo (lit. “from the beautiful stream”) may be latinization of the Lusatian town of Schönbach. See the brief note concerning Boncompagni's bibliographical study in M. Steinschneider, “Miscellen”, Hebräische Bibliographie, xi (1871), 57. Steinschneider also states that John was in Paris in 1297/98, but this is a confusion based on Boncompagni, “Intorno ad un trattato” (ref. 13), 740.

See, e.g., MS Paris, BnF, lat. 7422, fol. 1r, and the heading in Munich, BSB, Clm 5963, fol. 1r: “Nota quod causa efficiens huius libri dicitur fuisse Iohannes de Brunswic.” See further Cordoliani, “Les manuscrits” (ref. 23), 83.

MS Paris, BnF, lat. 7420A, fol. 38ra: “Causa efficiens huius operis fuit magister Iohannes de Pulcro Rivo qui ad preces quorundam sibi amicorum istud compendium compilavit et recollegitur in civitate que Parisius appellatur, ut ipsemet in fine huius operis astestatur.” Ibid., fol. 46va: “Explicit lectura compoti manualis edita Toloze Anno Domini M° CCC° XXXII.” In the commentary itself (fols. 39rb, 41vb) the present year is given as 1322. The other version of this commentary, dated 1305 (fol. 77vb), is found in MS London, BL, Royal 8. A. IX, fols. 76rb-81vb, a manuscript of Southern French origin. A gloss at the end (fol. 81vb) mentions the cost of frumentum in Toulouse in the year 1310. On this MS, see the Catalogue of Western manuscripts in the Old Royal and King's collections, ed. by G. F. Warner and J. P. Gilson (London, 1921), i, 211. For the Paris MS, see P. Meyer, “Traités en vers provençaux sur l'astrologie et la géomancie”, Romania, xxvi (1897), 225–75, pp. 227, 231–2. Both MSS are also mentioned in Boncompagni, “Intorno ad untratatto” (ref. 13), 736–40, and L. Thorndike, “Computus”, Speculum, xxix (1954), 223–38, pp. 224–5, 234.

This commentary is preserved in MS London, BL, Cotton Appendix LI, fols. 1r–5v, which was badly damaged by fire. The annus praesens is given as 1406 on fol. 4ra. A small fragment of fol. 4 was added as fol. 63 to MS London, BL, Cotton Galba A.V. A description of the former manuscript, with a partial transcription and English translation of the text, is found in S. H. O'Grady, Catalogue of the Irish manuscripts in the British Museum (London, 1926–53), i, 285–327. The date 1589 given in this description (ibid., 291) is a misreading of 1289, the original year of composition. Fragments of the same Irish commentary are also found in MS Dublin, Trinity College, 1314/4, fol. 1r–v. On the latter, see M. McNamara, The Psalms in the early Irish Church (Sheffield, 2000), 156.

See Thorndike and Kibre, A catalogue (ref. 23), col. 1401; Pedersen, The Toledan Tables (ref. 31), 161.

A very similar passage, mentioning Dionysius, Bede, Helperic, and “Garlandus in confinio Gallie et Germanie oriundus” occurs at the beginning of an anonymous commentary on John of Sacrobosco's Compotus ecclesiasticus, which follows upon the commentary on John of Brunswick's Compotus manualis in MS Paris, BnF, lat. 7422, fols. 17r–30v. The two references to Gerland in this manuscript were previously quoted in T. Wright, “Inedited notices relating to some early writers on the Compotus”, Transactions of the Royal Society of Literature, 2nd ser., ii (1847), 68–75, p. 73. The commentary on Sacrobosco has the incipit “Computus est scientia etc. Cum ista scientia apud veteres …”. See Pedersen, The Toledan Tables (ref. 31), 161; Cordoliani, “Les manuscrits” (ref. 23), 84. Two further copies appear in MSS London, BL, Harley 1, fols. 64r–70v, and Munich, BSB, Clm 10273, fols. 153r–63v. See Thorndike and Kibre, A catalogue (ref. 23), col. 225, who only list the Munich MS. On Sacrobosco's original text, see O. Pedersen, “In quest of Sacrobosco”, Journal for the history of astronomy, xvi (1985), 175-–221, pp. 184–5, 187–90, 206–14, and J. Moreton, “John of Sacrobosco and the calendar”, Viator, xxv (1994), 229–44.

Gudenus See V. F. , Sylloge I variorum diplomatariorum monumentorumque veterum ineditorum adhuc, et Res Germanicas in primis vero Moguntinas illustrantium (Frankfurt/Main, 1728), 352–3; Boncompagni, “Intorno ad un tratatto” (ref. 13), 724–5.

See refs. 6–7, 15 above.

See, e.g., MS Florence Plut. 30.24, fol. 90r: “Istud adieci propter partes meas scilicet Saxonie.” A slightly different reading is found in MS Vat. lat. 3112, fol. 41r: “Istud adiectum est propter partes nostras scilicet Saxonie.”

See refs 6–7, 24, 41 above. Glorieux, La faculté (ref. 23), 233, lists him as “Jean de Ponte Rivo” among the known thirteenth-century Arts masters, but provides no information beyond what can be inferred from the manuscripts of the Compotus manualis.

MS Vat. lat. 3112, fol. 56rb.

Poulle , “Les astronomes parisiens” (ref. 2), 49, thought he could integrate the Compotus novus into John of Saxony's biography by assuming a sufficiently large interval between the writing of the main treatise (1297) and the completion of the commentary in the 1320s, when John had moved to Paris to become an acolyte of Alfonsine astronomy. This scenario is completely voided, however, by the colophon in MS Vat. lat. 3112 and the one in the lost Mainz MS, which show that the commentary already dates from early 1298. See refs 17 and 45 above.

Narducci E. , Catalogo di manoscritti ora posseduti da D. Baldassare Boncompagni, 2nd edn (Rome, 1892), 78. This manuscript was auctioned at Bonhams, New York in 2011 (lot number 1009) and is now in private ownership.