Abstract
The church of Saint-Irénée in Lyons, the capital city of the Gauls, is one of the oldest witnesses of Christianization, and it also attests to the evolution of Lyons under the aegis of the Burgundians. New archaeological and historical data and a luminescence dating campaign presented here have renewed the previously held views on the development of the church of Saint-Irénée through the first centuries of its existence. Three main building stages were detected and the two first within a very short time span. According to the new data, the first building stage would have occurred between the 5th century and the beginning of the 6th century, the second one between the beginning of the 6th century and the beginning of the 7th century and the third one could be around the 9th-10th century period.Furthermore, we noticed that reused Gallo-Roman bricks were frequently set into the masonries which were studied in conjunction with the early medieval bricks that were specially produced for the (re)building stages already mentioned, which was unexpected.