1Ulpianus, On the Edict, Book XV. Possession on the ground of ownership exists where we think we acquire property for ourselves, and have possession of it under the title by which it was obtained, as well as because of ownership; as, for instance, when, by virtue of a purchase I hold possession both as purchaser and as owner. Moreover, I hold possession both as legatee and donee, and also on the ground of ownership, where property has been donated or bequeathed to me. 1Where, however, property has been delivered to me under some good title, for example, by that of purchase, and I acquire it by usucaption, I begin to hold possession of it as mine, even before acquiring it by usucaption. But can any doubt arise as to whether I cease to hold it, as purchaser, after usucaption has taken place? Mauricianus says that he thinks that I do not cease to hold it.

2Paulus, On the Edict, Book LIV. There is a kind of possession which is said to be based upon ownership. For in this way we possess everything which we acquire from the sea, the land, or the air, or which becomes ours by the action of the alluvium of streams. We also possess any offspring of property which we hold in the name of others; as, for instance, we hold as our own the child of a female slave belonging to an estate, or who has been purchased; and, in like manner, we possess the profits derived from property which has been bought or donated, or which constitutes part of an estate.

3Pomponius, On Sabinus, Book XXII. You delivered to me a slave whom you erroneously thought I was entitled to under the terms of a stipulation. If I knew that you did not owe me anything, I cannot acquire the slave by usucaption; but if I did not know it, the better opinion is that I can acquire him by usucaption, because the delivery, which was made for what I think to be a good consideration, is sufficient to enable me to possess as my own the property which has been delivered to me. Neratius adopted this opinion, and I think it is correct.

4The Same, On Sabinus, Book XXXII. If you purchased in good faith a female slave who had been stolen, and you have in your possession the child of said slave, that she conceived while in your hands, and, before the time prescribed for usucaption has elapsed you ascertain that the mother of the said child has been stolen, Trebatius thinks that the child which is possessed in this manner can unquestionably be acquired by prescription. I think that a distinction should be made in this case, for, if within the time prescribed by law for usucaption to take effect you do not ascertain to whom the slave belongs or if you knew this, without being able to notify the owner of the slave, or if you were able to notify him, and did it, you can acquire the slave by usucaption. If, however, you were aware that the slave had been stolen, and you could have notified the owner, but failed to do so, the contrary rule will apply; for you will be considered to have possessed her clandestinely, as the same person cannot possess property as his own and clandestinely at the same time. 1When a father divides his property among his children, and, after his death, they retain it, for the reason that it was agreed among them that this division of his estate should be ratified, usucaption on the ground of ownership will benefit so far as any property belonging to others, which may be found among the effects of the father, is concerned. 2Where property has not been bequeathed, but has been delivered as such by the heir through mistake, it is established that it can be acquired through usucaption by the legatee, because he possesses it as owner.

5Neratius, Parchments, Book V. The usucaption of property which we have obtained for other reasons than because we think that we are entitled to it as our own has been established in order to put an end to litigation. 1A person can acquire by usucaption the property of which he has possession, thinking that it belongs to him; even if this opinion is false. This, however, should be understood to mean that a plausible error of the party in possession does not interfere with his right to usucaption; for instance, if I possess some article because I erroneously think that my slave, or the slave of someone whom I have succeeded as heir at law, purchased it, as ignorance of the act of another is an excusable mistake.