Ad edictum praetoris urbani libri
Ex De testamentis libro primo
The Same, Concerning Wills; On the Edict of the Urban Prætor, Book I. The appointment of an heir, as follows, “Those whom Titius may wish”, is defective, for the reason that it depends upon the desire of another. For the ancient authorities very frequently decided that the validity of wills must be derived from themselves, and not depend upon the wishes of others. 1Anyone who is in the hands of the enemy can legally be appointed an heir, because, by the law of postliminium, all his personal rights of citizenship remain in suspense, and are not annulled. Therefore, if he should return from captivity he can enter upon the estate. His slave can also legally be appointed heir, and if his master returns from captivity, he can be ordered to enter upon the estate. If, however, he should die, his legal successor will become his heir through the act of the slave.
Gaius, On the Edict of the Prætor Relating to Wills. Where questions arise with reference to matters foreign to the will, they must receive a just and liberal interpretation; but those which arise concerning the will itself must be determined in strict accordance with the rules of the written law.