[IDEM libro quinto ad Plautium. ] §41.3.13.prPignori rem acceptam usu non capimus, quia pro alieno possidemus.
[THE SAME, On Plautius, book 5] We do not acquire by usucapion a thing received as a pledge, because we possess it as another's.
§41.3.13.1Eum, qui a furioso bona fide emit, usucapere posse responsum est.
It has been answered that he who buys in good faith from a madman can acquire by usucapion.
§41.3.13.2Si mandauero tibi, ut fundum emas, ex ea causa traditum tibi diutina possessione capis, quamuis possis uideri non pro tuo possidere, cum nihil intersit, quod mandati iudicio tenearis.
If I commission you to buy a tract of land, you acquire by long-term possession what has been delivered to you on that account, although you might seem not to possess it as your own, since it makes no difference that you are bound by the action on mandate.