Ptolemaeus Arabus et Latinus

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New Perspectives on Gerard of Cremona Second International Conference of the Project Ptolemaeus Arabus et Latinus (

Würzburg, Friedrich-Wilhelm-Joseph-Schelling-Forum

25–26 September 2024

Organisers: David Juste and Colette Dufossé

The reason for organising a conference on Gerard of Cremona is that a number of discoveries have been made about his scholarly activities in recent years. Gerard of Cremona (d. 1187) has long been known as the most prolific translator from Arabic into Latin in the Middle Ages. He translated over 70 scientific and philosophical texts, in the fields of logic, geometry, astronomy, natural philosophy, medicine, alchemy and divination, among which his greatest achievements are perhaps the translations of Ptolemy’s Almagest and Avicenna’s Canon. However, recent research conducted at Ptolemaeus Arabus et Latinus has shown that Gerard was not only a translator, but also an author, a commentator and a revisor of previous translations. The starting point was the discovery by Stefan Georges that Gerard produced a massive commentary on the Almagest. This discovery in turn led to the identification of similar commentaries on Ptolemy’s Quadripartitum and Pseudo-Ptolemy’s Centiloquium, and there are reasons to suspect that the same was done for other texts yet to be identified. We can also confirm earlier suggestions that Gerard revised and corrected preexisting translations, by Plato of Tivoli and others. Finally, in 2023, Stefan Zieme showed that in his translation of the Almagest, Gerard did not simply adopt the numerical tables as they appeared in his Arabic models, but recalculated them. These new perspectives invite us to reconsider Gerard’s scientific activity as a whole and to highlight his multifaceted scholarly endeavours.

Wednesday 25 September 2024


Doors open


Welcome address

Morning session – Chair: Dag Nikolaus Hasse


David Juste (Bayerische Akademie der Wissenschaften, Munich)

Gerard of Cremona Before this Conference: His Life and Works


Stefan Georges (Julius-Maximilians-Universität Würzburg)

Gerard’s Achievements: Some Additions


Coffee break


Andreas Büttner (Julius-Maximilians-Universität Würzburg)

Unveiling the Invisible Translator: A Computational Analysis of Gerard of Cremona’s Translation Style



Afternoon session – Chair: David Juste


Colette Dufossé (Bayerische Akademie der Wissenschaften, Munich)

Making the Almagest Accessible to Latin Readers: The Translation of Gerard of Cremona


Marc Moyon (Université de Limoges)

Gerard of Cremona and Some Geometrical Parts of MS Paris, Lat. 7377B: Euclid and Abū Bakr


Coffee break


Emanuele Rovati (University of Zurich)

Gerard of Cremona as an Astrologer


Charles Burnett (The Warburg Institute, London)

Gerard of Cremona’s Involvement in Alchemy, Geomancy, Divination and the Occult


Conference dinner

Thursday 26 September 2024

Morning session – Chair: Irene Caiazzo


Michael McVaugh (University of North Carolina at Chapel Hill)

How Did Gerard of Cremona Acquire His Technical Medical Latin?


Marina Díaz Marcos (Universidad de Castilla-La Mancha)

Gerard of Cremona: A Good Translator? Some Problems of Interpretation and Transcription in His Latin Translations of Greek Medical Texts Through Arabic


Coffee break


Danielle Jacquart (EPHE, PSL, Paris)

La traduction du Canon d’Avicenne: plusieurs intervenants?


Dag Nikolaus Hasse (Julius-Maximilians-Universität Würzburg)

Who Was the Translator of the Anonymous Latin Translations of Rhazes (Ibn Zakarīyāʾ al-Rāzī)?



Afternoon session – Chair: Colette Dufossé


Stefan Zieme (Humboldt-Universität zu Berlin)

45°: The Toledan Tables and the Latitude of Cremona


Philipp Nothaft (All Souls College, Oxford)

On the Liber omnium sperarum celi et compositionis tabularum, Allegedly Translated by Gerard of Cremona


Coffee break


Joel Chandelier (Université Paris 8)

New Light on the First Reception of Gerard of Cremona’s Medical Translations


John Mulhall (Purdue University)

A School in Toledo: Gerard of Cremona’s Teaching of the Sciences


Final discussion

David Juste (
Colette Dufossé (