Acquisition of ownership

There are many possible criteria for classifying the various ways of acquiring ownership under Roman law. Some means of acquiring ownership (like occupatio) were recognized by the law of nations, and others were regulated by civil law (like mancipatio, in iure cessio, or usucaption).

The most common way of acquiring ownership was by acquisition from the former owner. Valuable and more permanent things were conveyed by formal appropriation (mancipatio); other things were conveyed by mere delivery (traditio). To fix defects in the mode of transference, the Romans also established usucaption, which allowed individuals to gain civil property by continuous and uninterrupted possession of it.

Mancipatio and in iure cessio

The mancipatio constituted the means par excellence for transferring civil ownership of res mancipi. Gaius’s account of mancipatio is detailed (1.119— 122). The solemn ceremony of mancipatio took place in the presence of the alienator and the acquirer, as well as no fewer than five Roman citizens who acted as witnesses, and another Roman tasked with holding a scale. The things to be mancipated also had to be present at the ceremony, although lands could be mancipated at a distance. Taking hold of the mancipated thing, as a sign of control over it, the acquirer would say: “I declare this thing to be mine by civil law, and be it purchased to me by this bronze ingot and bronze scale.” He would then strike the scale with the ingot and pay a sym­bolic price to the alienator.

A guarantee in case of eviction (auctoritas), inherent to sale by mancipatio, was mentioned in the Twelve Tables (6.3). Over a period of one year for movable things and two years for immovable things, the transferee could bring an actio auctoritatis against the transferor (auctor) to compel payment of double the purchase price whenever a third party gained a claim of own­ership (rei vindicatio) against the transferee resulting in eviction. Originally, therefore, mancipatio was a real sale, but over time it became a formal act used for performances besides sales. It was used, for example, to make

testaments and donations and to constitute servitudes, dowries, and trusts, among other things. The legal transaction established by mancipatio appeared in additional declarations of the transferor (nuncupatio). Specific duties were also assumed by promises and mutual stipulations. Mancipatio was soon adapted for establishing, transferring, and extinguishing family powers by adoption or emancipation of children, noxal surrender, and so on. It disappeared gradually as the distinction between res mancipi and res nec mancipi lost significance, and written documents became more important. The word mancipatio does not appear in the Corpus Iuris of Emperor Justinian, and the concept was replaced by that of mere delivery (traditio).

Like mancipatio, transfer before the praetor - in iure cessio - was also a formal way of transferring civil property, but by fictitious litigation taking advantage of procedural formalities. Gaius (2.24) described the form: in the presence of the praetor, the acquirer said, while holding the item: “I declare that this thing is mine by civil law.” The praetor then asked the transferor to make a claim to the item and, based on the silence of the latter, formally attributed that item to the acquirer. Like mancipatio, the in iure cessio was used for many legal transactions such as the constitution of servitudes, the transfer of inheritances, and the establishment of adoption, tutelage, or cur­atorship.

Occupatio, accession, specification

Occupatio was an original and informal way of acquiring civil ownership that was recognized under the law of nations. It was the simplest way to become an owner: one only had to take an item that belonged to no one else (res nullius). Occupatio was the ordinary way to acquire wild animals captured by hunting or fishing, for example; after some disputes, Roman jurists agreed that wounded animals had to be seized to be acquired by occupatio (Gaius D. 41.1.5.1). Occupatio was also the way to acquire movable things that the owner had intentionally abandoned without intending to recover them. Immovable things required usucaption to be acquired.

Accessio was the way of acquiring property by uniting, merging, or mixing one’s property with another’s in a way that formed an indissoluble whole. It was what occurred, for example, when Titius would paint on Caius’s canvas; or when Titia’s wool was woven into Sempronius’s toga; or when Titius’s corn was sown on Caius’s land; or when Titius built on his own land with Caius’s materials. If the union of items was dissoluble, by contrast, there was no real acquisition by accession: for instance, if Titius could easily separate a jewel he had embedded in Sempronia’s ring. Neither was there acquisition by accession when the owners had previously agreed to mix things of equal quality; e.g., a mixture of different juices.

The general rule of accession was that the whole unit belonged to the owner of the principal thing, such that the owner of the incorporated

Property law 151 accessory thing lost property (Inst. 2.1.26). That happened regardless of whether the incorporation was effected in good faith or with the former owner’s consent. These latter circumstances were, however, relevant for determining the potential compensation to the owner who lost property.

It was often a matter of philosophical discussion what the principal thing was and what was accessory (see for instance Gaius, D.

Slightly different from accession was specification: the acquisition of a new thing (nova species) made out of materials belonging to another person: e.g., if Titius turned Caius’s bronze into a statue. The Sabinians ascribed ownership to the owner of the underlying materials, on the ground that a thing cannot exist without that of which it is made, while the Proculians gave ownership to the maker because the newly fashioned item as such had no previous owner. Emperor Justinian finally gave ownership to the maker, but only if the materials could not be restored to their former state (Gaius, D. 41.1.7.7).