It is at least thirty years since the first places of worship were identified beyond doubt in northern France. The constituent elements of a Gallic sacred site can be summarised as follows: a boundary ditch, generally quadrangular but sometimes oval, enclosed by a high wooden fence, with a monumental entrance door, an altar in the form of a trough or ditch surmounted by a building and having a grove of sacred trees outside, with damaged weapons, animal and human bones. These characteristics are remarkably similar to what was known in Classical Antiquity in the Mediterranean. The "Népellier" site at Nanteuil-sur-Aisne was interpreted in this way during its haphazard excavation in the 1960s, due to the discovery of broken weapons and human bones, but particularly following the identification of a fanum or sacred place. Its true importance was revealed by an aerial survey which showed the outlines of the Gauls' great oval ditch and the whole of the Roman temple. Another site ten kilometres away at Roizy, "Les Cinq Horles", showed similar features, a large oval enclosure and a Roman temple. Closer to Acy-Romance, the fanum excavated at the oppidum at Château-Porcien revealed pits containing large numbers of cattle horns. The large Roman temple at La Briqueterie does not seem to have been built on a Gallic sacred site. Discoveries of numerous objects, fibulas, Gallic and Roman coins, in small areas, seems to indicate the existence of less structured places of worship, with Ecly being a particularly good example. 

Nanteuil-sur-Aisne is close to and contemporaneous with Acy-Romance (1.5 km); it expanded during the Roman Empire and continued in use until the 4th century. For these reasons it appears to have been the principal sacred site for an area of Gaul comparable to a pagus or Roman district.