Four authors give lists of Celtic and German peoples in Gallia Belgica and Germania.

The earliest is J Caesar who mentions the names of the peoples allied with and opposed to Rome in the second half of the first century BCE.

He is followed by Strabo who's Geography, finished about 7 BCE, extends the list but omits some named by Caesar. Strabo presents the situation at the beginning of the first century BCE and names some German tribes that may well have been outside the two provinces.

The longest list is given by Pliny the elder (CE 24-79) who mixes the names of the peoples (civitates) with those of their sub divisions (pagi). Pliny takes account of the organisation of the provinces under Augustus and seems to indicate that many of the pagi has been given their independence. The Catustugae appear in the valley of the Bresle and the Tongri have be created from the Euberones and the Atuatuci.