USUCA'PIO. Gains (ii. 40-42) states that if a Res Mancipi was transferred by bare tradition, without the forms of Man cipatio or in Jure Cessio, the original owner retained the Quiritarian owner ship, and the person to whom the thing was transferred had only the right to the enjoyment of the thing until by posses sion he had acquired the ownership (pos sidendo usucapiat). For the effect of such enjoyment was to give him the same rights with respect to the thing as if it had been transferred in due legal form. In the case of moveables the Twelve Tables fixed one year as the term of Usu capio; in the case of land (fundus) and houses, two years. The acquisition of the Quiritarian ownership of a thing by enjoyment of it under the circumstances above stated for these several periods was called Usucapio.
Gains states that there might also be Usneapio in the case both of things Man cipi and things Nee Mancipi which had been transferred by bare tradition from a person who was not the owner, provided the transferree received them in good faith (bona fide), or, in other words, be lieved that he received them from the owner. It seems probable that this rule of law was established by analogy to the rule of the Twelve Tables as to Res Man cipi which had been transferred by defec tive modes of conveyance. But the Twelve Tables may have fixed only the time of Usucapio ; the origin of Usucapio may be anterior to the Twelve Tables.
When Gains wrote (in the second cen tury of our sera), Usucapio had become a regular mode of acquiring ownership ; for property of all kinds might be so ac quired which had been received by tra dition and bona fide from a person who was not the owner. The case of things stolen (by the law of the Twelve Tables), and a thing the possession of which had been acquired by violence (vis), was an exception (by the Lex Julia et Plautia), for even if received bona fide by a pur chaser, they could never become the pro perty of the receiver by Usucapio. The Res Mancipi of women also, who were in the tutela of their agnati, could not be objects of Usucapio unless they had been received from her by traditio with the proper consent (auctoritas) of her tutor ; and the hereditas of a woman who was in tutela legitima could not be an object of Usticapio. (Gains ii. 47; Cicero, Ad Attic. i. 5.) As land (fundus) could not, according to the best opinion, be an object of furtum, a bond fide purchaser of land from a man who was not the owner, and knew he was not the owner, might ac quire the property of it by Usucapio, pro vided the seller had not acquired the pos session by violence, but had either taken possession of land which was vacant through the carelessness of the owner, or from the owner dying without a succes sor, or having been long absent.
Besides individual objects of property, Usucapio could exist in the case of servi tutes (easements), and marriage, and in the case of an hereditas. Originally such serviettes as followed the rule of law as to Res Mancipi could only be trans ferred like Res Mancipi ; and therefore Usucapio could only apply to such servi tutes. But by analogy to Res Mancipi, they could be acquired by bare contract, to which Usucapio was superadded ; and when Mancipatio at a later period was replaced by bare tradition, they could be acquired by contract simply. In the case of marriage, when there was no co-emp tio, the woman might come into the power of her husband by virtue of uninter rupted cohabitation of one year ; and she was then said to become a part of his Fa milia by Usncapio founded on a year's possession. (Gains, i. 111.) In the case of the Hereditas, when the testator had not disposed of his property by the neces sary forms of the Mancipatio and Nun cupatio, the person who was named heres in the will could only acquire his legal title as such by Usucapio.
These various instances will show the original notion of Usucapio. It was a legal effect given to bond fide possession and uninterrupted enjoyment for a fixed time, by which defects in the transfer of a thing were made good : it was not ori ginally a mode of acquisition. It was founded on a title good in substance but defective in form ; and this defect was supplied by the proper period of enjoy ment (usus). When this uses had con tinued for the legal time it gave its auc toritas (as the Romans expressed it), its efficient y and completeness to what was in its origin incomplete, and the phrase Uses Auctoritas was older than the ex pression Usucapio, which was afterwards the ordinary term. But Usua by itself never signified Usucapio ; for Usus alone could not give a title to the ownership of a thing. In the case of public land the possessor had the uses, but this was all that he could be entitled to as possessor. Such mous could not from the nature of the case have an auctoritas, for the pos sessor did not occupy the public land as a bond fide purchaser. A man might also have the um of private land without having a title to anything further : in which case also the uses could never have an auctoritas.