[PAPINIANUS libro tertio decimo quaestionum. ] §28.7.28.prSi filius sub condicione heres erit et nepotes ex eo substituantur, cum non sufficit sub qualibet condicione filium heredem institui, sed ita demum testamentum ratum est, si condicio fuit in filii potestate, consideremus, numquid intersit, quae condicio fuerit adscripta, utrum quae moriente filio impleri non potuit, ueluti 'si Alexandriam ierit, filius heres esto' isque Romae decessit, an uero quae potuit etiam extremo uitae momento impleri, ueluti 'si Titio decem dederit, filius heres esto', quae condicio nomine filii per alium impleri potest.
[PAPINIANUS, in the thirteenth book of Questions.] If a son is to be an heir under a condition and his children (the grandchildren) are substituted for him, since it is not sufficient for a son to be instituted heir under just any condition, but the will is only valid if the condition was within the son's power, let us consider whether it makes a difference what kind of condition was added: whether it was one which could not be fulfilled when the son died, such as "if he goes to Alexandria, let the son be heir," and he died in Rome; or whether it was one which could be fulfilled even at the last moment of life, such as "if he gives ten to Titius, let the son be heir," which condition can be fulfilled by another person in the name of the son.
nam superior quidem species condicionis admittit uiuo filio nepotes ad hereditatem, qui si neminem substitutum haberet, dum moritur, legitimus patri heres exstiterit, argumentoque est, quod apud Seruium quoque relatum est: quendam enim refert ita heredem institutum, si in Capitolium ascenderit, quod si non ascendisset, legatum ei datum, eumque antequam ascenderet mortem obisse: de quo respondit Seruius condicionem morte defecisse ideoque moriente eo legati diem cessisse.
For the former kind of condition indeed admits the grandchildren to the inheritance during the lifetime of the son; this son, if he had had no one substituted for him, would have stood as the statutory heir to his father at the time of his death. And a case reported also in Servius serves as proof: for he reports that a certain person was instituted heir in this way, "if he should ascend the Capitol," but if he did not ascend, a legacy was given to him, and he died before he could ascend; concerning whom Servius answered that the condition failed by death, and therefore upon his death the right to the legacy was vested.
altera uero species condicionis uiuo filio non admittit nepotes ad hereditatem, qui substituti si non essent, intestato auo heredes existerent: neque enim filius uideretur obstitisse, post cuius mortem patris testamentum destituitur, quemadmodum si exheredato eodem filio nepotes, cum filius moreretur, heredes fuissent instituti.
But the other kind of condition does not admit the grandchildren to the inheritance during the lifetime of the son; these grandchildren, if they had not been substituted, would have stood as heirs to the grandfather upon his dying intestate. For the son, after whose death the father's will is rendered void, would not be deemed to have stood in the way, just as if, the same son having been disinherited, the grandchildren had been instituted heirs at the time the son died.