A man may institute as his heirs either free men or slaves, and either his own slaves or those of another man. If he wished to institute his own slave it was formerly necessary, according to the more common opinion, that he should expressly give him his liberty in the will: but now it is lawful, by our constitution, to institute one's own slave without this express manumission—a change not due to any spirit of innovation, but to a sense of equity, and one whose principle was approved by Atilicinus, as it is stated by Seius in his books on Masurius Sabinus and on Plautius. Among a testator's own slaves is to be reckoned one of whom he is bare owner, the usufruct being vested in some other person. There is, however, one case in which the institution of a slave by his mistress is void, even though freedom be given him in the will, as is provided by a constitution of the Emperors Severus and Antoninus in these terms: 'Reason demands that no slave, accused of criminal intercourse with his mistress, shall be capable of being manumitted, before his sentence is pronounced, by the will of the woman who is accused of participating in his guilt: accordingly if he be instituted heir by that mistress, the institution is void.' Among 'other persons' slaves' is reckoned one in whom the testator has a usufruct.

1 If a slave is instituted heir by his own master, and continues in that condition until his master's decease, he becomes by the will both free, and necessary heir. But if the testator himself manumits him in his lifetime, he may use his own discretion about acceptance; for he is not a necessary heir, because, though he is named heir to the testament, it was not by that testament that he became free. If he has been alienated, he must have the order of his new master to accept, and then his master becomes heir through him, while he personally becomes neither heir nor free, even though his freedom was expressly given him in the testament, because by alienating him his former master is presumed to have renounced the intention of enfranchising him. When another person's slave is instituted heir, if he continues in the same condition he must have the order of his master to accept; if alienated by him in the testator's lifetime, or after the testator's death but before acceptance, he must have the order of the alienee to accept; finally, if manumitted in the testator's lifetime, or after the testator's death but before acceptance, he may accept or not at his own discretion.

2 A slave who does not belong to the testator may be instituted heir even after his master's decease, because slaves who belong to an inheritance are capable of being instituted or made legatees; for an inheritance not yet accepted represents not the future heir but the person deceased. Similarly, the slave of a child conceived but not yet born may be instituted heir.

3 If a slave belonging to two or more joint owners, both or all of whom are legally capable of being made heirs or legatees, is instituted heir by a stranger, he acquires the inheritance for each and all of the joint owners by whose orders he accepts it in proportion to the respective shares in which they own him.

4 A testator may institute either a single heir, or as many as he pleases.

5 An inheritance is usually divided into twelve ounces, and is denoted in the aggregate by the term as, and each fraction of this aggregate, ranging from the ounce up to the as or pound, has its specific name, as follows: sextans (1/6), quadrans (1/4), triens (1/3), quincunx (5/12), semis (1/2), septunx (7/12), bes (2/3), dodrans (3/4), dextans (5/6), deunx (11/12), and as it is not necessary, however, that there should always be twelve ounces, for for the purposes of testamentary distribution an as may consist of as many ounces as the testator pleases; for instance, if a testator institutes only a single heir, but declares that he is to be heir ex semisse, or to one half of the inheritance, this half will really be the whole, for no one can die partly testate and partly intestate, except soldiers, in the carrying out of whose wills the intention is the only thing regarded. Conversely, a testator may divide his inheritance into as large a number of ounces as he pleases.

6 If more heirs than one are instituted, it is unnecessary for the testator to assign a specific share in the inheritance to each, unless he intends that they shall not take in equal portions; for it is obvious that if no shares are specified they divide the inheritance equally between them. Supposing, however, that specific shares are assigned to all the instituted heirs except one, who is left without any express share at all, this last heir will be entitled to any fraction of the as which has not been disposed of; and if there are two or more heirs to whom no specific shares have been assigned, they will divide this unassigned fraction equally between them. Finally, if the whole as has been assigned in specific shares to some of the heirs, the one or more who have no specific shares take half of the inheritance, while the other half is divided among the rest according to the shares assigned to them; and it is immaterial whether the heir who has no specified share come first or last in the institution, or occupies some intermediate place; for such share is presumed to be given to him as is not in some other way disposed of.

7 Let us now see how the law stands if some part remains undisposed of, and yet each heir has his share assigned to him—if, for instance there are three heirs instituted, and each is assigned a quarter of the inheritance. It is evident that in this case the part undisposed of will go to them in proportion to the share each has assigned to him by the will, and it will be exactly as if they had each been originally instituted to a third. Conversely, if each heir is given so large a fraction that the as will be exceeded, each must suffer a proportionate abatement; thus if four heirs are instituted, and to each is assigned a third of the inheritance, it will be the same as if each had been originally instituted to a quarter.

8 If more than twelve ounces are distributed among some of the heirs only, one being left without a specific share, he will have what is wanting to complete the second as; and the same will be done if more than twenty-four ounces are distributed, leaving him shareless; but all these ideal sums are afterwards reduced to the single as, whatever be the number of ounces they comprise.

9 The institution of the heir may be either absolute or conditional, but no heir can be instituted from, or up to, some definite date, as, for instance, in the following form—'be so and so my heir after five years from my decease,' or 'after the calends of such a month,' or 'up to and until such calends'; for a time limitation in a will is considered a superfluity, and an heir instituted subject to such a time limitation is treated as heir absolutely.

10 If the institution of an heir, a legacy, a fiduciary bequest, or a testamentary manumission is made to depend on an impossible condition, the condition is deemed unwritten, and the disposition absolute.

11 If an institution is made to depend on two or more conditions, conjunctively expressed,—as, for instance, 'if this and that shall be done'—all the conditions must be satisfied: if they are expressed in the alternative, or disjunctively—as 'if this or that shall be done'—it is enough if one of them alone is satisfied.

12 A testator may institute as his heir a person whom he has never seen, for instance, nephews who have been born abroad and are unknown to him: for want of this knowledge does not invalidate the institution.