6 Wills, however, which, though duly executed, are subsequently rescinded by the testator's undergoing loss of status are not altogether inoperative: for if the seals of seven witnesses are attached, the instituted heir is entitled to demand possession in accordance with the will, if only the testator were a citizen of Rome and independent at the time of his decease; but if the cause of the rescission was the testator's subsequent loss of citizenship or of freedom, or his adoption, and he dies an alien, or slave, or subject to his adoptive father's power, the instituted heir is barred from demanding possession in accordance with the will. 7 The mere desire of a testator that a will which he has executed shall no longer have any validity is not, by itself, sufficient to avoid it; so that, even if he begins to make a later will, which he does not complete because he either dies first, or changes his mind, the first will remains good; it being provided in an address of the Emperor Pertinax to the Senate that one testament which is duly executed is not revoked by a later one which is not duly and completely executed; for an incomplete will is undoubtedly null. 8 In the same address the Emperor declared that he would accept no inheritance to which he was made heir on account of a suit between the testator and some third person, nor would he uphold a will in which he was instituted in order to screen some legal defect in its execution, or accept an inheritance to which he was instituted merely by word of mouth, or take any testamentary benefit under a document defective in point of law. And there are numerous rescripts of the Emperors Severus and Antoninus to the same purpose: 'for though,' they say, 'the laws do not bind us, yet we live in obedience to them.' TITLE XVIII. OF AN UNDUTEOUS WILL Inasmuch as the disinherison or omission by parents of their children has generally no good reason, those children who complain that they have been wrongfully disinherited or passed over have been allowed to bring an action impeaching the will as unduteous, under the pretext that the testator was of unsound mind at the time of its execution. This does not mean that he was really insane, but that the will, though legally executed, bears no mark of that affection to which a child is entitled from a parent: for if a testator is really insane, his will is void. 1 Parents may impeach the wills of their children as unduteous, as well as children those of their parents. Brothers and sisters of the testator are by imperial constitutions preferred to infamous persons who are instituted to their exclusion, so that it is in these cases only that they can bring this action. Persons related to the testator in a further degree than as brothers or sisters can in no case bring the action, or at any rate succeed in it when brought.