After Caesar's conquests, ''Gallia Belgica'' came to be the Latin name of a large Roman province covering most of Northern Gaul, including the Treveri. Areas closer to the lower Rhine frontier, including the eastern part of modern Belgium, eventually became part of the frontier province of ''Germania Inferior'', which interacted with Germanic tribes outside the empire. At the time when central government collapsed in the Western Roman Empire, the Roman provinces of Belgica and Germania were inhabited by a mix of a Romanized population and Germanic-speaking Franks who came to dominate the military and political class.