[FLORENTINUS libro decimo institutionum. ] §28.5.50.prSi alienum seruum liberum et heredem esse iussi et is postea meus effectus est, neutrum ualet, quia libertas alieno seruo inutiliter data est.
If I have ordered a slave belonging to another to be free and to be my heir, and he afterwards becomes mine, neither is valid, because freedom was invalidly given to another's slave.
§28.5.50.1In extraneis heredibus illa obseruantur: ut sit cum eis testamenti factio, siue ipsi heredes instituantur siue hi qui in potestate eorum sunt, et id duobus temporibus inspicitur, testamenti facti, ut constiterit institutio, et mortis testatoris, ut effectum habeat.
In the case of stranger heirs, the following rules are observed: that there must be testamenti factio with them, whether they themselves are instituted heirs or those who are in their power; and this is inspected at two times: at the time the will is made, so that the institution may be established, and at the death of the testator, so that it may take effect.
hoc amplius et cum adibit hereditatem esse debet cum eo testamenti factio, siue pure siue sub condicione heres institutus sit: nam ius heredis eo uel maxime tempore inspiciendum est, quo adquirit hereditatem.
In addition to this, also when he enters upon the inheritance, there must be testamenti factio with him, whether he was instituted heir unconditionally or under a condition; for the right of an heir is to be inspected most especially at that time when he acquires the inheritance.
medio autem tempore inter factum testamentum et mortem testatoris uel condicionem institutionis exsistentem mutatio iuris heredi non nocet, quia, ut dixi, tria tempora inspicimus.
However, a change of status in the intervening time between the making of the will and the death of the testator, or the fulfillment of the condition of the institution, does not harm the heir, because, as I have said, we inspect three times.