CASE 118: The Uniqueness of the Son-in-Power

Gaius, Institutiones 3.104

Praeterea inutilis est stipulatio, si ab eo stipuler, qui iuri meo subiectus est, item si is a me stipuletur.

(Gaius in the third book of his Institutes)

Further, a stipulation is ineffective if I stipulate from a person who is subject to my power; and likewise, if he stipulates from me. But in the case of a slave, a per­son who is in mancipium, a daughter-in-power, and a wife in manus, they cannot be (legally) obligated not only to the person to whose power they are subject but also to anyone else.

1.      No Obligations within the Familia. The principle in the first sentence ap­plies more broadly than just to stipulations, and it runs in both directions. For example, Pomponius, D. 44.7.7: “Actions cannot be provided to a son against his father while the son is in his power.” What this means, in part, is that promises made within the familia, between a pater and his children, can­not be enforced by law. Is this consistent with the general nature of the Roman household?

2.      Sons and Daughters. Gaius's list in the second sentence is notable for its pointed omission of sons-in-power; for, as we shall see, if sons are otherwise qualified (of adult age, sane, and so on), they possess full capacity to contract with a third party. By contrast, as Gaius says, daughters-in-power (and also wives in archaic manus marriages) cannot be obligated to anyone; that is, they lack the capacity to make a contract that is binding upon themselves.

3.      Slaves. It may seem more logical that slaves cannot themselves be direct par­ties to obligations either within or without the familia. However, as it turns out, this is not entirely accurate even as to relationships between a slave and his owner, since, for instance, slaves could sometimes make valid contracts with a view to their future manumission (e.g., Ulpian, D. 4.3.7.8).

4.      Natural Obligations. Even if the contracts of slaves or daughters were not legally enforceable when made, they were not entirely without legal effect. They are referred to as obligationes naturales, with the result, for instance, that if the daughter or slave performs as promised, the value of that performance cannot be reclaimed as not having been originally owed. See, for example, Paul, D. 12.6.13 pr. (a slave).