The rules affecting this matter are of gradual development: they are, in the main, a result of three principles, not wholly consistent with each other, and are themselves modified by the increasing recognition of the individuality of the slave. The three principles are:

1. 1. Noxa caput sequitur, a rule applied to delicts.

2. 2. In matter of contract, the slave naturaliter obligat et obligatur.

3. 3. The slave on manumission becomes a new man (and on reenslavement, another man again). The change is analogous to capitis deminutio, but it does not amount to this, as a slave has no caput. Servile caput nullum ius habet, ideo nee minui potest: servus manumissus capite non minuitur, quia nullum caput habet

So far as concerns delicts to the slave, there is not much to be said. The only one which can well be conceived is iniuria, and we are told, emphatically, that he can have no remedy for that after manumission. A theft of the man, or damnum to him, is a delict against his dominus, with whom the right of action remains, notwithstanding manumission of the slave. If the slave stolen or injured were instituted and freed by his dominus, he would presumably acquire these rights of action as he did others. This is implied by two texts which deal with an exceptional case. We are told by Ulpian, Marcian and Marcellus that if a slave who has been injured is instituted by his dominus, with liberty, and then dies, his heres will have no actio Aquilia. Marcian gives as the reason the fact that the case is now in a position in which the right of action could not possibly have arisen.