The basic administrative unit in Roman Britain. They were derived from existing British tribes, and were governed by a council drawn from the local landowners, who used a local town (the civitas capital) as their centre of government.
The name given to a territory occupied by a conquered tribe
the city and surrounding territory served as a basis of the administrative system in the Frankish kingdom. (p. 236)
In the history of the Roman empire, civitas (pl. civitates) mainly referred to the condition of Roman citizenship. It was also used to describe a type of settlement.
Civitas: The Institute for the Study of Civil Society was launched early in 2000 as an independent think tank. It is a British registered charity (No. 1085494). It is politically non-partisan and is financed by private donations.