[ULPIANUS libro trigensimo sexto ad Sabinum. ] §29.1.28.prCum filius familias miles decessisset filio impubere herede instituto eique substituisset in aui potestate manenti tutoresque dedisset, diui fratres rescripserunt substitutionem quidem ualere, tutoris autem dationem non ualere, quia hereditati quidem suae miles qualem uellet substitutionem facere potest, uerum tamen alienum ius minuere non potest.
[ULPIANUS, in his thirty-sixth book on Sabinus.] When a soldier who was a filius familias died, having instituted his impuberal son—who remained under the power of his grandfather—as heir, and had substituted another for him, and had also appointed tutors for him, the Divine Brothers replied by rescript that while the substitution was indeed valid, the appointment of tutors was not; for a soldier can indeed make whatever substitution he wishes with respect to his own inheritance, but he cannot, nevertheless, diminish another's right.