AP1<h2>Several works arranged in a chronological order</h2> This manuscript exhibits, in a way, the history of medieval astronomy and its different phases. Indeed, it includes various works from Al-Fargani's Liber de scientiae stellarum (some kind of compendium of Ptolemaic astronomy dating from the 9th century) to 15th&nbsp;century treatises in the movement of the skies, all arranged in a chronological order.

AP2<h2>A History of Astronomy Manuscript in the form of a Library</h2> The variety and texts, and the aforementioned organization of the works tend to indicate that this manuscript has been designed as a toolbox for a reader who was in need of easily accessible references and texts, thus arranged in an orderly fashion. It may have primarily been a student manuscript, more than tools used by a seasoned practitioner of astronomy. Reading marks, notes, diagrams and calculations were added afterwards in the margins, on blank pages or on leaflets. Adding content might have been more important to the owner(s) of the manuscript than the aesthetics or the readability, since many comments were added while the letterheads remained at the project state. Apart from the main scribe, texts have been copied with two other hands, and the marginal annotations give examples of at least four scribal hands: one of Jo.B., two gothic from the second half of the 15th century and a humanistic one from the beginning of the 16th century.

AP3<h2>In search of the scribes, owners and readers identities</h2> The manuscript as a whole was assembled during the 15th century, and the name of the main scribe was a certain « Jo. B » (probably John...) whose monogram is visible for instance on folios 85v, 160r, 232r and 273r.&nbsp;

AP3a<h2>In search of the scribes, owners and readers identities</h2> At the very end of the manuscript, folio 284v we can read, by different hands, the names « Loys Lepuiset » and « Johannes Avis », who may have been owners of the manuscript.

AP3b<h2>In search of the scribes, owners and readers identities</h2> After the Renaissance, we can trace it back to the Bibliotheca Colbertina in the 17th century, a collection of more than 8000 volumes that has been transferred to the Royal Library of France in 1732. The red leather cover of the manuscript (or “Royal Morocco binding”) is yet again&nbsp;embossed with the gold royal seal.

AP3c<h2>In search of the scribes, owners and readers identities</h2> The stamp&nbsp;« Bibliotheca Regis » is visible on folios 1r and 279r. The shelfmark&nbsp;attributed to this manuscript during the 19th century reorganisation of the National Library of France, also appears. Judging from these elements, the names of the supposed owners, the milieu of the authors of the 13th-15th works included in this manuscript, the places of reference for the marginal calculations scribbled in it, we can safely assume that it has been produced, read and stored in Paris, thus giving us an overview of the parisian astronomy of the late Middle Ages and Renaissance era.

AP4<h2>Many words and only a few illustrations</h2> Moreover, the manuscript is mostly textual, with no illuminations, no paper instruments, and only few illustrations and diagrams.

AP4a<h2>Many words and only a few illustrations</h2> Among those, the diagram drawn in the upper margin of folio 143r is noteworthy. It represents the apparent retrograde motion of Mars described in the text, to help the reader picturing the phenomenon in his mind and – since it is from the same hand as the text itself – it assumed the function of an alternative way of depicting it.

AP6<h2>A paper manuscript tells a story</h2> It is particularly noticeable here that this manuscript has been written on paper and not on parchment. Paper was less expensive and allowed access to the texts by less fortunate people but it also had its disadvantages : unlike parchment, it cannot be scratched to erase errors. One had then to overstrike the text to delete faulty elements or to write between lines to add new elements or notes. This kind of interventions makes the manuscript look less polished but tell us about its life, the various steps it went through, thus giving us hints about the production context, the number and diversity of agents (readers and copists), the type of use they made of the text etc.

AP7<h2>Ways of easily navigating in the texts</h2> The organisation of the text can be made manifest by various techniques. On this folio, the copist used rubrication (use of various colors to sections with red ink) and red letterheads. These elements of color were added later than the black ink text. The scribe first copied the main text, and left blank spaces (lines for the titles and empty squares for the letterhead) and indications (the small black letters to be converted to red capitals). The different arguments presented have also been sometimes identified and numbered in red in the right margin.&nbsp;

AP8<h2>Several writing phases</h2> Sometimes, this posterior pass on the text was an opportunity to revise it and to proceed to some corrections and redaction of miscopied passages.

AP9<h2>A reader's way to highlight important passages</h2> Many reading marks are visible in the margins of the manuscript, and some of them are designed to draw attention to important passages of the texts, to comment, to use or to memorize them. For instance, « manicule » are drawings of human hands that, literally, point to certain paragraphs.

AP10<h2>Various types of signs</h2> Trefoils or speckles are also commonly drawn in the margins with the same purpose of emphasizing passages.

AP11<h2>A work yet to be studied</h2> The Tractatus de Magnitudine, Distantia et Motu Astrorum (ff . 248v – 252v) have not yet been attributed to any known author.

AP11a<h2>Details and evidence to be investigated</h2> In the upper margin of this folio, an indication seems to read « credo quod … huius libri fuit magister Johannes de Troyes quia hoc tempore 1420 finit Parisius volentissimus» with the date « 1420 ».

AP11b<h2>A beautifully decorated letterhead</h2> On another level, we can notice that this work and the following have been carefully and meticulously rubricated. The first letterhead is ornate with a foliage inspiration, the pilcrows are inked in red.

AP11c<h2>Highlights and colored ink are not used only for esthetic purposes</h2> More importantly, some words and numerical values are underlined in red, in the text as the marginalia. Those elements worthy of notice according to the copist can be numbers used for computation.

AP12<h2>The names of authorities are made visible too</h2> They can also be authorities like, here, Abu Ishaq ibn Yahya Al-Zarqali (Azarchel in latin), author of the Toledan Tables, or Abu Mas'har al-Balkhi (Albumazar), famous in Western Medieval Europe for his work translated in Latin under the title « De magis conjunctionibus ».

AP13<h2>A manuscript is not a once and for all finished artifact</h2> This manuscript includes nine added folios. They consist of leaflets, smaller than the pages of the manuscript, that have been inserted between pages or glued in the binding later. They sometimes are textual additions and are intended to give more details on the matters discussed.

AP14-AP5<h2>Complementary leaflets can be added to a manuscript decades or century afterwards</h2> Sometimes, they are clearly from a different hand and posterior date than the main text, like this leaflet entitled « Ad componendum tabulae eclipsionis solis secundum observationes alphonsine » (how to compose tables for eclipses of the sun according to alfonsine observations).

AP15<h2>Reconstructing the interests and practices of the writer from the numerical values displayed</h2> These two leaflets (234bis and ter) are notes, drawings and computations made by a posterior reader of the text, judging by the hand. It can inform the discerning historian of astronomy about the computation practices of the past. It also bears information about the location and interests of the writer in composing his « Pro solario fabricando per tables », since he calculated positions of the sun « pro regio 50 gradum » (50 degrees latitude) and « 48. 50 » that refers to the latitudes of the parisian and norman regions.

AP16-22<h2>Blank pages turned into post-its</h2> Other kinds of notes can be found in this manuscript, letting us know that it has been used as a toolbox and a notebook. For instance, here, notes on the position of the sun for the meridian of Paris location (48.50) have been written on some page left blank by the folded quires conception of the manuscript. One can recognize the horoscope symbols for the signs Cancer and Capricorn.

AP17<h2>Adding some diagrams and tables is a further step than copying the text</h2> On some folios, spaces are left blank for latter addition of diagrams or tables. For instance, on this folio, the sentence « tempus eclipsis lune [eius] quantitatem et eius durationem per tabulas invenire” is underlined and seems to indicate that the addition of a table for the computation of moon eclipses was planned in the large blank space on the left.

AP18<h2>A work that is typical of Ptolemaic astronomy</h2> The very first part of the manuscript consists of Ptolemaic astronomy (9th-11th centuries), since it contains Al-Farghani's De scientia astrorum (ff. 1r-15v), a 9th century treatise, originally written in Arabic and translated in Latin during the 12th century by Gerard of Cremona and John of Sevilla that soon became the basis of the teaching of astronomy in the Western World. While respecting the principles of Ptolemaic astronomy, Al-Farghani corrected some values given by Claudius Ptolemy in his Almagest. But the De scientia astrorum was above all a theoretical compendium, and during the Middle Ages up to the Renaissance, it was considered an introduction to the general notions of astronomy more than as a treatise of mathematical astronomy. It has been largely copied and printed over the centuries.

AP18a<h2>Editing ancient texts implies taking care of all the different versions of a said work</h2> A note from the 17th century indicates that « this version differs from the Nuremberg edition of 1537 and the Parisian one of 1546 available at the librarian dominus Arnaudi Pratoris Forcalcaris » (« ista versio diversa est a versione que edita est Noribergae anno 1537 et Parisius anno 1546 apud bibliotheco Arnaudi Pratoris Forcalcaris »), telling us that this version is the translation by Gerard of Cremona.

AP19<h2>Toledan astronomy treatises</h2> The second part of the manuscript consists of Toledan Astronomy Treatises (12th and 13th centuries). It goes from folio 17r to folio 156v and, alongside a commentary on the Tables of Toledo and the canons, it includes works from John of Sicily and William of Saint-Cloud that are representatives of the pre-Alfonsine stage of the parisian astronomy at the turn of the 14th century.

AP20<h2>A lecture on a classical way of using the Toledan Tables has been added in this Toledan Astronomy section of the manuscript</h2> This work is entitled « Lectiones tabularum Toletanarum secundum Arzachelem Hispanem secundum rationem Caldaeorum ». It is written in a different hand than the main scribe and has been carefully rubricated and even decorated.

AP20<h2>A delicately decorated letterhead</h2> The letterhead for the word « Incipiunt » (« here begin ») has been traced with black ink and decorated with orange and red ink dots.

AP21<h2>How to use astronomical tables in an optimal way is a delicate matter relying on inventiveness and resourcefulness</h2> The second work of this part consists in Canons for the Toledan Tables and goes from folio 30r to 42r. It visually is the most dense text of the manuscript, with a hasty cursive hand and an impressive number of textual layers : plain text, underlined text, diagrams, marginal notes, references and calculations, overstroke notes, intertitles, and an added leaflet.

AP23<h2>Parisian astronomers before Alfonsine astronomy</h2> Inserted in a gloss to this text by William of Saint-Cloud (the Kalendarium Reginae), we can distinguish a mention of a « Petrus Dacus » that refers to Peter of Dacia. Given the fact that the previous works in the manuscript are by John of Sicily, and the works by Wlliam of Saint-Cloud are followed by blank pages, it draws our attention to the fact that the first owner of the manuscript chose to regroup authors of the same periods and currents. William, John and Peter can, indeed, be considered the core of the pre-Alsonsine parisian astronomers.

AP24<h2>A turning point work by John of Murs</h2> The manuscript continues its pathway through the history of astronomy, entering the 14th century Latine Alfonsine astronomy with the Expositio intentionis regis Alfontii circa tabula eius by John of Murs, a work dated from c. 1325 considered to be one of the first written evidence of the use of the Alfonsine Corpus in the Parisian milieu.

AP25<h2>Anti-Alfonsine astronomy works have been written, though</h2> But the acceptance of Alfonsine astronomy did not occur without a fight. For instance, Geoffrey of Meaux in his Calendar for the year 1320 states that he rejected the Alfonsine tables. The same author also wrote an « Exposition of the Alfonsine Tables and reasoned proof of their falsity (Expositio tabularum Alfonsine et motiva probantia falsitatem earum) which has been copied here folios 172v to 174v. Nonetheless, the takings into account, debates, further elaborations of the Alfonsine astronomy make this author part of the same current and milieu as John of Lignères, John of Saxony and John of Genoa whose works are included in the manuscript.&nbsp;

<h2>AP26</h2><h2>Astronomy was conceived and practiced in close relation with other disciplines during the Mid﻿dle Ages, particularly medicine and astrology. </h2> The presence here of this treatise by Nicole Oresme (1320-1382), a brilliant philosopher and mathematician known for his opposition to judgements astrology, further underlines the variety and comprehensiveness of the texts copied in this manuscript. Oresme devoted numerous texts, in Latin and French, more or less technical depending on the intended readership, to the criticism of astrology. And in addition to moral and political reasons relating to the defense of human free will and distrust of the influence of court astrologers on public affairs, he relies on geometrical reasons.

AP26a<h2>Drawings about geometrical incommensurability to help figure out its implications in astronomy</h2> Thus, in De commensurabilitate vel incommensurabilitate motuum celi, he geometricaly demonstrates the incommensurability of bodies moved on circular motion and, consequently, of the planets. He concludes that if the calculation of the positions of one celestial body in relation to all the others cannot lead to values that can be expressed in rational numbers, conjunctions of celestial bodies are probably impossible. The astronomer would have to be satisfied with values with an infinite number of decimal places, which necessarily calls for truncations and approximations to handle these numbers.

AP26b<h2>Oresme analyses geometricaly the very possibility of celestial conjunctions</h2> Therefore, the astrologer who bases his predictions on recurrences in the positioning of the celestial bodies, and who speaks of conjunctions or oppositions between the planets, is in fact basing his predictions on imprecise results, which call into question the very validity of a theory of astrological prediction.

AP26c<h2>A dream about sciences</h2> This treatise closes with Oresme’s dream featuring the personifications of Geometry and Arithmetic debating over this subject in front of Apollo, and their debate is as much about astrology as it is about astronomy, or the very status of numbers.

AP27<h2>Astral medicine was an important field of medieval sciences but surprisingly, this medical work here is not related to astral sciences !</h2> Another peculiarity of Latin 7281’s content is that its last work on folios 279v-282v (Tabula magistri Jacobi de Partibus sive Tabula sirupi ad omnes humores) is touching upon a medical subject without any correlation to astronomy or medical astrology. This outstanding text is the classification of various remedies by Jacques Despars (1380-1458), a French physician, most well-known as a commentator of Avicenna, and could be explained by the fact that the manuscript has been owned by a physician Jean Avis, a dean of the Faculty of Medicine at the University of Paris between 1470 and 1471 (not to be confused with two other people named Jean Avis: his son, who obtained a Master degree in medicine in 1502, and the third John Avis, who was also a dean of the Faculty of Medicine in 1504-1506 and was the physician of Louis XII, and then of François I).

AP28<h2>John Avis : scholar, physician and astrologer</h2> Here we can decipher the signature of Johannes Avis. He has been the dean of the Faculty of Medicine at the University of Paris between 1470 and 1471. In addition, he was highly interested in astrology and was acquainted to the famous&nbsp;astronomer and astrologer Simon de Phares (who has made great contribution to the history of astronomy and astrology by leaving a text mentioning famous astronomical actors of his time – “Recueil des plus célèbres astrologues”), to whom Jean Avis could have lent Latin 7281.&nbsp;

Manuscript with an exceptional content : a history of astronomy through texts, conceived during the second half of the 15th century.