As We have heard of an instance in which an ambiguous testament had been submitted for interpretation, We have thought it proper that the decision of the question should be made the subject of a positive law; for We are accustomed to make such transactions the occasion for the enactment of better legislation.
  (1) A certain man, when appointing his children heirs, desiring that the survivors should be substituted for those who might die before them, ordered that if any one of his children who would be his future heir should die without issue, everything which he left him, except that to which he was entitled by law, and all other property and rights of which he was possessed at the time of his death, should be transferred to the survivor of the other children, or to the offspring of the said survivor if the latter himself should die, releasing them from giving any bond or security, by reason of the substitution of the aforesaid property. The testator, having died, left as his heirs one son who had children, and another who had none. He who had children forbade the other to take the substituted property, on the ground that he would diminish its value. The latter, however, relying upon the words of the will, namely: "That he should deliver whatever was in his possession at the time of his death," claimed to have the right to use the property in any way he pleased, without being prevented from so doing in any way whatsoever.
  (2) Therefore We, taking advantage of this opportunity, have deemed it necessary to dispose of the ancient legislation, and settle this matter for the future, to treat the subject with clearness, and to include this case in a law, in order that judges may learn how to hear and determine others of a similar character. We are aware that the most wise Papinianus, in the Nineteenth Book of his "Questions," allows ambiguous alienations to be made in instances of this kind; he discusses the point of ascertaining when it is necessary to prohibit, and he thinks that this should only be done where a trust is to be executed by the person who is charged with it. And the philosophical Emperor Marcus also disposed of a similar case in which the judgment of a good citizen seemed to be required to determine the meaning of words under such circumstances.

  Therefore We consider it advisable to establish the rule that where a testator, in general terms, directs the property to be delivered by the terms of a trust, what We have already decreed in cases of this description shall be observed. When, however, the trust resembles the one which has been referred to Us, and the testator only subjected to delivery such property as might be found at the time of the death of the person charged with the execution of the trust, then what has been prescribed by former laws shall be complied with. When the bequest of the testator is of this nature, or in some respects resembles the one above mentioned, We order that he who is charged with the execution of the trust shall only be required to preserve for the substitute the amount of the Falcidian portion, the contribution of which is compulsory, and that he cannot absolutely deduct anything from the said Falcidian portion, but the three-fourths of the estate to which he was appointed heir shall remain in the hands of the trustee, and only a fourth of the same shall be reserved for the benefit of the substitute. We do not permit the trustee to make donations, for the purpose (as Papinianus said) of defeating the object of the trust, in order to diminish the fourth of the estate referred to, but We decree that he shall preserve this portion of the trust for the substitute; that all of the remainder shall belong to him, and that he shall be at liberty to make use of it as the true owner, in whatever way he wishes. If the heir charged with the trust should acquire the fourth that he ought to reserve, the reason for his doing so should be ascertained; and if having no other property he should desire to constitute a dowry or to make an ante-nuptial donation, he shall be permitted to do so, as is stated in the preceding law, by which We have not absolutely prohibit a trustee from making a diminution of this kind in a trust. He shall also have authority to diminish the fourth reserved by the substitute for the redemption of captives (for We make an exception in this instance and dedicate it to God), as We are actuated by motives of piety which seem to Us to be the most precious of all things.

  If, however, the trustee should not have enough to defray his expenses, he can, for that purpose, make use of the property to be delivered under the trust, and We grant him permission to do so (for this was the intention of the testator) desiring the remainder to be transferred, just as if the testator had expressly stated that delivery of the remaining property should be made after the expenses were paid. But where the trustee has no ground for encroaching upon the fourth of the estate which he is obliged to transfer, he will be compelled to preserve it all and deliver it to the substitute. If he has paid out anything on account of the substituted property, he must take enough from some other source to make up the said fourth, which, as has just been stated, shall, on no account, be diminished. When, however, the trustee has obtained the fourth of the substitution, and has nothing himself out of which to make up the deficiency, We, by the terms of this law, grant the substitute the right to bring an action in rem against the purchasers, or other persons who have received the property, in order that the terms of the trust may be complied with through the recovery of said property, a privilege which we have already conceded with reference to legacies, by authorizing the legatee under Our Constitution to bring an action in rem in order to be able to execute the trust. Wherefore the heir charged with the trust must give security to preserve at least the fourth of the substituted property, unless the testator excuses him from doing so, as he did in the case referred to Us; for when the testator releases the heir not only from the necessity of furnishing security, but also from that of executing a bond, We will not act in conformity with his wishes if We prescribe otherwise.

  This decision is rendered with reference to the proceedings which gave rise to it, as well as to all others concerning wills, where the testators are dead; and it also applies to trusts which have not yet been carried out for the reason that the heirs charged with their execution are still living. We decree that these provisions shall be observed not only so far as children are concerned, but also with reference to other relatives and strangers, who are charged with the execution of a trust of this kind. Your Glory will communicate this law to all Our subjects, so that they may learn how they should live, die, make wills, create trusts, and comply with the other provisions ordered under similar circumstances.