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

Ptolemaeus Arabus et Latinus

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Project Outline

  1. The project Ptolemaeus Arabus et Latinus is dedicated to the edition and study of the Arabic and Latin versions of Ptolemy’s astronomical and astrological texts and related material. This ‘Corpus Ptolemaicum’ includes three categories of texts:

    1. Ptolemy’s authentic works, comprising the Almagest, the Tetrabiblos and the minor works Planetary Hypotheses, Phaseis, Analemma, Planisphaerium, and Handy Tables.

    2. Pseudepigrapha (works falsely attributed to Ptolemy), i.e. mainly the Centiloquium, but also other astronomical and astrological works, about 30 of which are known in Arabic and Latin.

    3. Commentaries on the texts under A and B above.

  2. General aim – The aim of the project is to provide a full treatment of the Corpus Ptolemaicum, including a catalogue of manuscripts (§3 below), editions of the texts (§§4-6), and various tools and studies towards a better understanding of Ptole­my’s reception in the Arabic/Islamic world and Latin/Christian Europe up to 1700 A.D. (§§7-8).

  3. Catalogue of manuscripts – The catalogue of manuscripts will describe all surviving Arabic and Latin manuscripts (and early printed editions) of the Corpus Ptolemaicum, categories A, B and C. It is anticipated that this catalogue will include at least 100 Arabic and 500 Latin manuscripts.

  4. Editions (Authentic works and pseudepigrapha, A-B) – The edition of the Corpus Ptolemaicum (categories A and B) will take place in three steps, as follows:

    1. Digital reproductions: each text (and each version in cases of multiple translations) will receive an online digital reproduction in scanned form from one or more selected witnesses (manuscripts or early printed edition), so as to make the primary material available to scholars at an early stage of the project. The digital reproductions will be accompanied by reading aids, such as a ta­ble of contents listing all chapters and diagrams, with links to the relevant pages of the manuscript.

    2. Online transcriptions: the digital reproductions will be gradually linked with online standardised transcrip­tions, so as to make each text searchable. State of the art technology will be used, so that, for example, parallel passages in the various translations of the same text can be easily compared. Technical terms will be linked to the glossary (§7.1 below), so that defi­nitions as well as occurrences in other texts can be found immediately.

    3. Critical editions: the online transcriptions will be gradually supplemented by proper critical editions based on examination of all extant manuscripts.All works of the Corpus Ptolemaicum under A (authentic works) and B (pseudepi­grapha) will receive a critical edition. In cases of multiple translations, only the most influential Arabic and Latin versions will be edited. The critical edition will be published in the PAL book series Ptolemaeus Arabus et Latinus (Brepols) and the plain text (i.e., without introduction and critical apparatus) will be published online.

  5. Editions (Commentaries, C) – Texts of category C (commentaries, including glosses found in the manuscripts) will be the subject of a critical survey and the most important of them will be edited following the three-step procedure described above. As far as possible, digital reproductions and online transcriptions (§4.1-2) will be provided for all texts, but only the most significant of them will be critically edited (§4.3). ‘Significant’ refers to influential texts which played an important role in conveying Ptole­my’s ideas and especially those texts which expand on, correct, question or criticise Ptolemy’s original texts (as opposed to mere paraphrases and commentaries for educational purposes). It is anticipated that a dozen substantial texts or groups of shorter texts will receive a critical edition. These will definitely include Jābir ibn Aflaḥ’s Iṣlāḥ al-Majisṭī and its Latin translation by Gerard of Cremona; the anonymous Almagesti minor; and both the Arabic and Latin versions of ʿAlī ibn Riḍwān’s commentary on the Tetrabiblos and of Abū Jaʿfar’s commentary on the Centilo­quium. Besides the commentaries proper, there are numerous Arabic and Latin works which relate to Ptolemy less directly, such as basic expositions of Ptolemaic astronomy (e.g. al-Farghānī and the Theorice planetarum), attempts to provide a physical basis for Ptolemy’s planetary models (e.g. Ibn al-Haytham), or works seeking to bring these models in accordance with Aristotle’s physical principles (e.g. al-Biṭrūjī). While these works are not commentaries on Ptolemy in the strict sense – and hence are not included in the treatment described above, they will nevertheless be examined and decisions may be made to edit those unstudied works which are particular­ly relevant to the project, again following the three-step procedure described above.

  6. Astronomical tables, almanacs and horoscopes – Special attention will be given to astronomical tables, almanacs (or ephemerides) and horoscopes, insofar as they represent the main products of medieval and early modern astronomical and astrolo­gical activity in the Ptolemaic tradition. The aim here will be to design and maintain a database of these sources, to produce a critical survey of them and to edit some of the most representative and/or influential ones.

  7. Tools

    1. Greek-Arabic-Latin glossary – An online Greek-Arabic-Latin glossaryof astronomical and astrological terms with technical/historical commentary, designed as a constantly growing online tool based on the texts already edited in the project.

    2. Computer programs for editing and analysing astronomical tables, almanacs and horoscopes – These programs will provide convenient means for entering numerical data from a variety of sources and producing critical apparatuses for them. Furthermore, they will offer a range of pos­sibilities for analysing the mathematical properties of, and the relationships between, various types of astronomical data.

  8. Studies – The project will inevitably give rise to new questions, the most important of which will be the subject of international conferences and workshops (§10.1 below), and will lead to independent publications.Special attention will be paid to the following three research areas, for which the relevant documents will be assembled throughout the project:

    1. The reception of Ptolemy in the Arabic world and Western Europe up to 1700 A.D.

    2. A comparative study of Arabic and Latin astronomy and astrology in their historical context.

    3. The place of Ptolemy in the Copernican Revolution.

  9. Output – The project is divided into 38 modules (research units), which can largely be carried out independently from each other and most of which will result in a major in-print publi­cation and/or its online equivalent. The completion of most modules will require the full-time work of one scholar over a period of 3 to 5 years, with the exception of the critical editions of the Arabic Almagest, the Latin Almagest and the Latin pseudepi­grapha, which are expected to take up to 10 years each.

  10. International cooperation

    1. Organisation of 8 international conferences and workshops.

    2. Partnership with the Warburg Institute (University of London). This partnership will take the form of an exchange programme of PhD students and postdoctoral researchers, joint supervision of doctoral students, and joint organisation of workshops and conferences, some of which will take place at the Warburg Institute.

    3. Visiting fellowships. Over the course of the project, visiting scholars will be invited to work with the research team in Munich for a period of 1-4 months. Among these there will also be specialists of Greek, Syriac, Hebrew and Persian scientific texts.

  11. The project is funded by the Union der deutschen Akademien der Wissenschaften and hosted by the Bayerische Akademie der Wissenschaften in Munich for a period of 25 years starting in 2013. The project is supervised by Prof. Dr. Dag Nikolaus Hasse (University of Würzburg) and carried out by five scholars as follows: two research leaders, Dr David Juste (formerly University of Sydney) and Dr Benno van Dalen (formerly University of Munich); two postdoctoral researchers; and one doctoral student. The staff of the project also includes a computer scientist, a secretary and two student assistants.


See also the special issue of Akademie Aktuell. Zeitschrift der Bayerischen Akademie der Wissenschaften 03/2013, pp. 8-45, with a general presentation of the project and articles by Alexander Jones, Paul Kunitzsch, Charles Burnett, Noel Swerdlow, Dag Nikolaus Hasse, David Juste and Benno van Dalen.


For further information, please contact David Juste, Benno van Dalen or Dag Nikolaus Hasse at