The following classification, while it is strictly adapted to the notions of the Romans, gives us the peculiar terms of their ancient national law.

Ager, a district, was the whole territory belonging to any civic community, in opposition to terra, a country, which comprised many such proprietary districts, as for instance terra Italia, Graecia. All landed property (ager in its restricted sense) was either Roman or forein, aut Romanus aut peregrinus. Under the head of forein came even that of isopolitan nations.

All Roman land was either the property of the state (common land, domain), or private property, aut publicus aut privatus.

The landed property of the state was either consecrated to the gods (sacer), or allotted to men to reap its fruits (profanus, humani juris). A later view made this the primary division, and then distinguisht the land belonging to man into public property and private property: but a treatise, evidently written in the time of Domitian, and assuredly by Frontinus—the only work among those of the Agrimensores which can be accounted a part of classical literature, or was composed with any real legal knowledge—says that the soil of the sacred groves was indisputably the property of the Roman people. This is confirmed by the statement in Livy that the temple and grove of Juno at Lanuvium became the joint property of the Roman people and of the Lanuvine municipals when the latter were admitted to the civic franchise.