On restoration of things which our enemy has taken from another in an unlawful war

We have explained above to what extent things become the property of the captors by a lawful war. From such things, we must deduct those which are recovered by right of postliminy;…for these are regarded as not having been captured.

But we said that that which was taken in an unlawful war must be restored, not only by those who took it, but also by others to whom the thing has come in any manner whatsoever. For no one, the authorities of the Roman law declare, can transfer to another more right than he himself has.…The person who first took the thing did not have moral ownership (dominium internum); therefore, the person who obtains his right from him will not have it. [H]ence the second or third possessor takes an ownership which, for the sake of explanation, we call legal (externum), that is, an ownership which has the advantage of being everywhere protected by the authority and power of the courts. Nevertheless, if the possessor uses this advantage against him from whom the thing was taken by an act of injustice, he will not act rightly.