The many Galens of the medieval commentators on vision.

It is my aim in this paper to discuss some aspects of the relationship between medieval medical authors and classical authorities. Historians of medicine have stressed the academic activities of medical masters as those of conciliation and explanation of authority. I will rather suggest that the explanation of classical authority was not the main aim of the medical masters but, in fact, its very construction. I would like to develop this possibility by analysing the nature of the approach to visual perception in academic medical circles at the end of the thirteenth century and the beginning of the fourteenth century.