Definition and Classification of Res

The Roman concept of res did not remain fixed but underwent considerable devel­opment as its use changed following the evolution of society and economic relations.

The Roman jurists classified things by reference to their physical nature, usage or the technical legal rules that applied in respect thereof. The various classifications formulated by the jurists are generally the result of historical devel­opment and represent an attempt at systematizing the relevant part of private law.

3.2.1      Res in Nostro Patrimonio and Res Extra Nostrum Patrimonium

A very early classification of things was between things that could form part of the private estate or assets of an individual, or within the sphere of trade (res in nostro patrimonio or res in commercio), and things that were not susceptible to private ownership, or outside the sphere of trade (res extra nostrum patrimonium or res extra commercium).^[280]

The res extra nostrum patrimonium were, in turn, sub-classified into things subject to divine law or under the protection of the gods (res divini iuris) and things subject to human law that accrued to all people collectively (res humani iuris).^[281] The former category encompassed things dedicated to the heavenly gods by an act of the state (res sacrae), such as temples, altars, chapels and groves^[282]; things consecrated to the gods of the underworld (res religiosae), such as cemeteries; and things deemed to be under the protection of the gods because of the purposes they served (res sanctae), such as the walls and gates of a fortified city.^[283]

Res humani iuris that were not capable of being privately owned included things deemed common to all mankind (res communes), such as the air, running water, the sea and its shores^[284]; things belonging to the state for use of its citizens (respublicae), for example public roads, bridges, harbours, market places and so forth^[285]; and things belonging to a particular city or municipality for the use and enjoyment of its inhabitants (res universitatis),^[286] such as theatres, public baths, sports grounds, halls of justice and the like.name="_ftnref287" title="">^[287]

3.2.2      Res Corporales and Res Incorporales

With respect to the res in nostro patrimonio (or res in commercio), a distinction was drawn between corporeal (res corporales) and incorporeal things (res incorporales).

It is important to note that ownership as such was not considered to be a res incorporalis, as ownership could only exist over a corporeal thing and, in this respect, the thing and the ownership right over it formed an indivisible entity. An individual can possess a corporeal object and have rights, such as ownership, over it. However, a res incorporalis cannot be understood in this way since it is not possible to have a right over a right. The right is the abstract relationship between a person and a legally recognized interest, but is not itself the interest. From the Roman jurists' perspective, describing a right as a res incorporalis was only a convenient manner of referring to an interest associated with a particular person by virtue of a legal relationship.

Although primarily academic and philosophical in nature, the distinction between res corporales and res incorporales had some practical importance. This emanated from the fact that only corporeal things could be possessed and conse­quently several legal concepts with respect to which possession played an essential part were not applicable to res incorporales. Because incorporeal objects could not be physically seized as required for possession to exist, they thus could not be acquired or transferred by any method involving the acquisition or transfer of possession.^[289]

3.2.3      Res Mancipi and Res Nec Mancipi

The most important classification of things in commercio in the pre-classical and classical law was between res mancipi and res nec mancipi.

The origin of the distinction between res mancipi and res nec mancipi has been the subject of much controversy among contemporary historians and many explan­atory theories have been advanced. All we can say with certainty is that the distinction is related to the fact that certain things were considered as extremely valuable in early times when agriculture played an important role in social and economic life, and were therefore placed in a separate category. It is possible that the original list of things classified as res mancipi was different, but at any rate in the later republican age the relevant categories had become fixed and arbitrary.^[292]

As the formal methods for the transfer of ownership became obsolete in the later imperial age, the distinction between res mancipi and res nec mancipi gradually fell into desuetude to the extent that it had vanished by the time of Justinian's reign.^[293]

A classification of things belonging to the category of res corporales distinguished between movables (res mobiles) and immovables (res immobiles).

3.2.5       Other Classifications of Res

During the republican era a distinction was made between land in Rome and land in Italy confiscated as bounty of war, the so-called ager publicus. Land in Rome was subject to private ownership, but the ownership of the ager publicus was vested in the Roman people as a whole. In the course of time, portions of the ager publicus were sold by auction or were leased on rent to private individuals thereby providing a source of funds for the public treasury, while a large part of it was apportioned amongst citizens (especially army veterans).^[295] The public lands sold or given away became private property. In the closing years of the Republic a distinction was introduced between land in Italy and land in the provinces. At this stage Italic land was privately owned but the ownership of provincial land was vested in the state, in either the Roman people or the emperor. The ager publicus in the provinces was vast, though in time most of this land also fell into private hands.

Reference should also be made to the distinction between generic and specific things. The former were determined in accordance with their type (genus), for example a slave and a bag of barley, whilst the latter indicated a specific thing (species), for example the slave Valerius or the first bag of barley.^[296] Generic things that could usually be measured, counted or weighed were regarded in later law as replaceable (res fungibiles), in contradistinction with specific things that were irreplaceable (res nonfungibiles).

Another important distinction existed between divisible things, that is, things that could be divided without either of the divided portions being damaged or diminished in value (e.g. wheat), and indivisible things which encompassed those that could not be divided without damage or loss of economic value (e.g. a cart).^[298] Furthermore, some things could form a unit that is either composite (universitas rerum cohaerentium), for example a house or a cabinet, or consisting of entirely separate objects (universitas rerum distantium), such as a herd of cattle.

Finally, reference may also be made to fruits (fructus) as a thing or things derived from another principal thing. Such fruits normally became the property of the owner of the principal thing, although there were certain legal situations in which a person had a right to the fruits from another person's property.^[299] Fruits that originated naturally from a thing, such as the fruit of trees, the offspring of animals, milk and wool, were distinguished from civil or legal fruits arising from the use of property through legal transactions, for instance the rent from a lease.^[300] Natural fruits were further divided into fruits not yet separated from the principal thing that produced them (fructus pendentes), fruits separated from the principal thing (fructus separati), and fruits separated and gathered (fructus percepti). A final distinction was that between fruits already consumed (fructus consumpti) and fruits still existing that were not consumed (fructus extantes).

3.2.6      Real and Personal Actions and Rights

Unlike modern law that places the emphasis on rights, Roman law placed the emphasis on remedies; in other words, on the forms of action rather than the causes of action. The remedy to which a person had recourse when he considered his interests had been impaired or under threat was the crucial factor: because he had recourse to such a remedy, he had a right. An individual’s interests could pertain to property or obligations, the difference between the two being the difference between owing and being owed. This difference found expression in the distinction between real actions (actiones in rem) and personal actions (actiones in personam).^[301] By an action in rem, the plaintiff sought to establish the strength of his claim to a legal right over movable or immovable property as opposed to a claim of the defendant or to compel the latter to acknowledge such a right.^[302] A real action was founded on the claim that the plaintiff had a better right to something than anyone else in the world, and could be instituted against anyone who invaded or disputed such right. With respect to such an action, the plaintiff had to formulate his claim by identifying the missing content of his property right and, in so doing, refer to the party against whom the claim was instituted. An actio in personam, on the other hand, was initiated by the plaintiff to enforce performance by the defendant arising from an existing contractual or delictual obligation.^[303] Such an action was based on a specific obligation and directed against a determinate person or persons.^[304]

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