ALFA Conference 2021

Alfonsine Astronomy: mathematical practices

05.10. 2021-07.10.2021


Organisation: José Chabás, Richard Kremer, Matthieu Husson


The central scientific aim of ALFA’s second phase is to “analyse the Alfonsine astronomers’ practices, their relations to mathematics, to the natural world, to proofs and justification, their intellectual context and the audiences they addressed”. To tackle this aim, we will focus more specifically on the mathematical practices attested in the Alfonsine corpus. The kernel of the astronomers’ practices is mathematical: the kind of numbers and quantities they shaped, their relation to computations, rounding and interpolation, their use of diagrams and instruments, their use of standardized procedures, or their attitude toward proofs and justification.

It will be important to analyse each of these different layers of mathematical practices, ranging from numbers and quantities to procedures and argumentation, on its own sake by asking specific questions about the ways Alfonsine astronomers engaged with them in order to address astronomical problems and produce various types of solutions, be they computational, graphical, tabular, or most often a mix thereof. It will be also important to consider, from the manuscript evidence, how these different layers of the Alfonsine mathematical practices are articulated in order not only to provide solutions to astronomical problems but also to reveal self-reflexive understandings and evaluations of these astronomical problems by the historical actors.

Thus, we seek to come closer to the Alfonsine astronomers’ practices and to assess more precisely what kind of mathematical astronomy they fostered and what were its main lines of tension and development over the course of the 14th and 15th centuries. This, in turn, will enrich our understanding of the attitudes of Alfonsine astronomers on broader issues like empirical observation, relation to natural philosophy, or links to astrology or medicine.

This conference is the second of two scheduled for this set of issues (the first took place in 2020). In this second meeting, our aim is to discuss draft paper for the collective book so that extensive place will be given to discussion among team members in a collective “referee” process.


Albouy Ségolène, Andriani Eleonora, Bui Camille,Glen Van Brummelen; Chabás José, Dot Tristan,  Gessner Samuel, Hadrava Petr, Hadravova Alena, Husson Matthieu, Jacobson Nick, Kremer Richard,  Miolo Laure, Penin Jean-Claude, Saby Marie-Madeleine, Samso Julio, Serra Sophie, Tur Alexandre, Zieme Stefan


October Tuesday 5


Author: Samuel Gessner, Nick Jacobson, Eleonora Andriani

Commentators: Marie-Madeleine Saby, Sophie Serra


Author:Alena Hadravova

Commentators:Alexandre Tur, Marie-Madeleine Saby


Author: Samuel Gesner, Marie-Madeleine Saby

Commentators:José Chabas, Eleonora Andriani


Author:José Chabas

Commentators: Nick Jacobson, Stefan Zieme


Author: Nick Jacobson

Commentators: José Chabas, Laure Miolo


October Wednesday 6



Author: Petr Hadrava

Commentators: Samuel Gessner, Richard Kremer


Author:Jean-Claude Penin

Commentators: Matthieu Husson, Camille Bui


Author: Eleonora Andriani, Stefan Zieme

Commentators: Rich Kremer, Laure Miolo


Author:Richard Kremer

Commentators: Glen Van Brumellen, Petr Hadrava


Author: Glen Van Brummelen

Commentators: Jean-claude Penin, Samuel Gessner


October thursday 7


Author: Alexandre Tur

Commentators: Eleonora Andriani, Alena Hadravova


 Author:Samuel Gessner

 Commentators:Petr Hadrava, Matthieu Husson


Author: Matthieu Husson

Commentators:Stefan Zieme, Glen Van Brummelen


Author:Seb Falk


General discussion current project and future plans