THE 1ST OF AUGUST AT LUGDUNUM: ASTRONOMY AND IMPERIAL CULT IN GALIA

Abstract

The longstanding debate about the interpretation of the Concilium Galliarum, celebrated at Lugdunum on Augusts 1st has been traditionally divided among those in favor of a ‘Celtic’ tradition and those advocating for a ‘Roman’ praxis. We advocate, following the works by Audin, that the study of the urban layout may shed light into this controversy. We find that this Roman grid has a remarkable orientation consistent with the orientation towards the rising sun on days close to this festivity. The location of the main sanctuaries of the city, the municipal sanctuary devoted to the imperial cult and the Three Gaul sanctuary, situated on both sides of the river, reveals interesting astronomical relations. These could be interpreted as an attempt at the time of the early Empire to include the Augustus and Rome cult even in areas with a strong pre-existent tradition, like the Gaul.