Ownership - Duality of
Title and Possession
Res Mancipi and Res Nec Mancipi
In ancient Roman law, physical property became classified into two categories;
"Res Mancipi" - things that required a mancipation"; and
"Res Nec Mancipi" - things that did not require a mancipation.
"Mancipium" or mancipation was a formal public ceremony required for recognition of conveyance in "title" of legal ownership to a thing, (mancipatio - taking in hand.) The ceremony included striking a scale with a copper ingot as a token of sale. Without this ancient ritual, no exchange had the sanction or protection of the law.
Another manner of acquiring legal title was cessio in iure, ( cession in court,) by vindicatio. An individual claiming title against a possessor would physically claim the thing (or a part of it produced in court.) If the possessor failed to also claim the thing by exceptio, the praetor would restore it to the individual claiming title.
This distinction between categories of things ceased in the Roman Law at the time of Justinian, but was carried forward in the development of English law.
Res Mancipi generally encompassed those properties most valuable to agriculture - land, houses, slaves and four footed beasts of burden. Under Roman law, the list of Res Mancipi was irrevocably closed. In English law, the distinction was carried forward with the identity of res mancipi as "immovables" governed by the laws of "realty" and res nec mancipi as "movables," chattel or goods, governed by the laws of "personalty."
Res Nec Mancipi did not require the ceremony of mancipium for conveyance, only simple delivery or traditio. Res Nec Mancipi were considered on a "lower footing of dignity" allowing for freer circulation of common objects of use and enjoyment. The list of Res Nec Mancipi could be expanded to accommodate new valued items. Transfer of ownership of Res Nec Mancipi was evidenced by physical "delivery."
Roman law also formally recognized the distinction between the incorporeal web of social relationships inherent in the concept of ownership, as well as the thing or object being "owned." "Tradition" applicable to Res Mancipi recognized two elements in conveyance of ownership: (1) the consent or intent to transfer ownership title to the thing; and (2) the physical delivery of the thing into the new owner's possession. Mancipation was the ceremony by which the incorporeal legal title was symbolically passed. Title to things not requiring mancipation was presumed to have passed with corporeal delivery.