CENSUS, in Roman antiquity, an authentic declaration made before the censors, by the several subjects of the empire, of their respective names and places of abode. This declaration was registered by the censors; and contained an enumeration, in writing, of all the estates, lands, and inheritances they possessed; their quantity, quality, place, wives, children, domestics, tenants, slaves. In the provinces the census served not only to discover the substance of each person, but where, and in what manner and proportion, taxes might be best imposed. The census at Rome is commonly thought to have been held every five years; but Dr Middleton hath shown, that both census and lustrum were held irregularly and uncertainly at various intervals. The census was an excellent expedient for discovering the strength of the state; for by it they discovered the number of the citizens, how many were fit for war, and how many for offices of other kinds; how much each was able to pay of taxes, &c. It went through all ranks of people, though under different names: that of the common people was called census; that of the knights, census, recensio, recognitio; that of the senators, lectio, relectio.—Hence also census came to signify a person who had made such a declaration; in which sense it was opposed to incensus, a person who had not given in his estate or name to be registered.
The census, according to Salmasius, was peculiar to the city of Rome. That in the provinces was properly called professio and ἀπογραφή. But this distinction is not everywhere observed by the ancients themselves.