Civitas

The agreement (concilium) has a life of its own, creating a res publica or "public entity" (synonymous with civitas), into which individuals are born or accepted, and from which they die or are ejected.

As the empire grew, inhabitants of the outlying Roman provinces would either be classed as dediticii, meaning "capitulants", or be treated as client states with some independence guaranteed through treaties.

During the later empire, the term was applied not only to friendly native tribes and their towns but also to local government divisions in peaceful provinces that carried out civil administration.

A basic street grid would be surveyed in but the development of the civitas from there was left to the inhabitants although occasional imperial grants for new public buildings would be made.

All this activity was administered by an ordo or curia, a civitas council consisting of men of sufficient social rank to be able to stand for public office.

Towards the end of the empire, the civitates' own local militias, led by a decurion, likely served as the only defensive force in outlying Romanised areas threatened by barbarians.

There is evidence that some civitates maintained some degree of Romanisation and served as population centres beyond the official Roman withdrawal, albeit with limited resources.