Le groupe cathédral de Grenoble (Isère) : essai sur ses origines

The present arrangement of the cathedral, as well as medieval tradition and the dual dedication to St Vincent (now St Hugh) and Notre Dame, are reminiscent of a double church, until now considered medieval one, founded by Charlemagne himself according to legend. Scholars have long thought that the ancient cathedral was located outside the walls in Saint-Laurent. Jean Hubert and Paul-Albert Fevrier were the first to suggest that the origin of the double church might be older than medieval, but they lacked proof: an undated apse in the eastern side of the cloister south of Notre-Dame and a complex stratigraphy under St Hugues were juged insufficient proof. Since 1989, part of the tetrarchic curtain wall and a portion of the "Viennoise" gateway, a forth century construction built against this wall and a small funerary area were found in an excavation in front of the cathedral and suggested a Christian occupation as early as the fourth century. Anyhow from the very fifth century there existed a baptistery in front of the present cathedral: originally rectangular, endowed with an eastern apse, thereafter turned in a tetraconch. Meanwhile, the baptismal pool became narrower in depth and breadth. Light traces of the northern and eastern arcades of an atrium, in front of what could have been an ancient double cathedral, have been discovered.