The interpreters, who preceded him, are not agreed on this point, one of the most difficult in the ancient Roman law. The conclusions of Hume, of which the author here speaks, inaccurate notions of Property among the Romans, and those of many authors in the present day are not less erroneous. We think it right, in this place, to develop the system of property among the Romans, as the result of the study of the extant original authorities on the ancient law, and as it has been demonstrated, recognized, and adopted by the most learned expositors of the Roman law. Besides the authorities formerly known, such as the Fragments of Ulpian, t. xix. and t. i. 16. Theoph. Paraph. i. 5, 4, may be consulted the Institutes of Gaius, i. 54, and ii. 40, et seq.
The Roman laws protected all property acquired in a lawful manner. They imposed on those who had invaded it, the obligation of making restitution and reparation of all damage caused by that invasion; they punished it moreover, in many cases, by a pecuniary fine. But they did not always grant a recovery against the third person, who had become bona fide possessed of the property. He who had obtained possession of a thing belonging to another, knowing nothing of the prior rights of that person, maintained the possession. The law had expressly determined those cases, in which it permitted property to be reclaimed from an innocent possessor. In these cases possession had the characters of absolute proprietorship, called mancipium, jus Quiritium. To possess this right, it was not sufficient to have entered into possession of the thing in any manner; the acquisition was bound to have that character of publicity, which was given by the observation of solemn forms, prescribed by the laws, or the uninterrupted exercise of proprietorship during a certain time: the Roman citizen alone could acquire this proprietorship. Every other kind of possession, which might be named imperfect proprietorship, was called "in bonis habere." It was not till after the time of Cicero that the general name of Dominium was given to all proprietorship.
It was then the publicity which constituted the distinctive character of absolute dominion. This publicity was grounded on the mode of acquisition, which the moderns have called Civil (Modi adquirendi Civiles ). These modes of acquisition were
This last mode of acquisition completed the system of civil acquisitions, by legalizing, as it were, every other kind of acquisition which was not conferred, from the commencement, by the Jus Quiritium. V. Ulpian. Fragm. i. 16. Gaius, ii. 14. We believe, according to Gaius, 43, that this usucaption was extended to the case where a thing had been acquired from a person not the real proprietor; and that according to the time prescribed, it gave to the possessor the Roman proprietorship. But this does not appear to have been the original design of this Institution.
Caeterum etiam earum rerum usucapio nobis competit, quae non a domino nobis tradita fuerint, si modo eas bona fide acceperimus Gaius, l ii. 43.
As to things of smaller value, or those which it was difficult to distinguish from each other, the solemnities of which we speak were not requisite to obtain legal proprietorship. In this case simple delivery was sufficient.
In proportion to the aggrandizement of the Republic, this latter principle became more important from the increase of the commerce and wealth of the state. It was necessary to know what were those things of which absolute property might be acquired by simple delivery, and what, on the contrary, those, the acquisition of which must be sanctioned by these solemnities. This question was necessarily to be decided by a general rule; and it is this rule which establishes the distinction between res mancipi and nec mancipi, a distinction about which the opinions of modern civilians differ so much that there are above ten conflicting systems on the subject. The system which accords best with a sound interpretation of the Roman laws, is that proposed by M. Trekel of Hamburg, and still further developed by M. Hugo, who has extracted it in the Magazine of Civil Law, vol. ii. p. 7. This is the system now almost universally adopted. Res mancipi (by contraction for mancipii) were things of which the absolute property (Jus Quiritium) might be acquired only by the solemnities mentioned above, at least by that of mancipation, which was, without doubt, the most easy and the most usual. Gaius, ii. 25. As for other things, the acquisition of which was not subject to these forms, in order to confer absolute right, they were called res nec manci mancipi. Their enumerations do not quite agree; and various methods of reconciling them have been attempted. The authority of Ulpian, however, who wrote as a civilian, ought to have the greater weight on this subject.
But why are these things alone res mancipi? This is one of the questions which have been most frequently agitated, and on which the opinions of civilians are most divided. M. Hugo has resolved it in the most natural and satisfactory manner.
"All things which were easily known individually, which were of great value, with which the Romans were acquainted, and which they highly appreciated, were res mancipi. Of old mancipation or some other solemn form was required for the acquisition of these things, an account of their importance. Mancipation served to prove their acquisition, because they were easily distinguished one from the other."
On this great historical discussion consult the Magazine of Civil Law by M. Hugo, vol. ii. p. 37, 38; the dissertation of M. J. M. Zachariae, de Rebus Mancipi et nec Mancipi Conjecturae, p. 11. Lipsiae, 1807; the History of Civil Law by M. Hugo; and my Institutiones Juris Romani Privati p. 108, 110.
As a general rule, it may be said that all things are res nec mancipi; the res mancipi are the exception to this principle.
The praetors changed the system of property by allowing a person, who had a thing in bonis, the right to recover before the prescribed term of usucaption had conferred absolute proprietorship. (Pauliana in rem actio.) Justinian went still further, in times when there was no longer any distinction between a Roman citizen and a stranger. He granted the right of recovering all things which had been acquired, whether by what were called civil or natural modes of acquisition, Cod. l. vii. t. 25, 31. And he so altered the theory of Gaius in his Institutes, ii. 1, that no trace remains of the doctrine taught by that civilian.