Thanks to archaeological surveys conducted in the French pre-alpine lakes, a significant number of lacustrine sites dating back to the Roman period have been discovered. One of them, discovered in 2000, in the waters of Lake Bourget, has been the subject of recent and deeper research. Dendrochronology, ceramology and numismatic findings have made it possible to determine a coherent chronological time line (second half of the second century AD.). The individual observation of the artefacts highlights the cultual nature of the site. A large quantity of data has been acquired including localization, morphology, the presence of bark, species, annual growth rings, slaughter phases and seasons, etc. through topography in addition to the removal and analysis of numeroussamples of wood from posts and stakes. Cross referencing all this information provides some insight into the development and function of the site.