[Iustiniani Institutiones]

... [Notes on manumission, natal status, and the legal recognition of the state of persons].

if a pregnant slave woman has been manumitted, and then becomes a slave again, she produces a free child. If she produces a slave, Marcellus proves he is born free. For it is sufficient for him that he had a free mother in the womb or in the intermediate time, which is also true. But when an ingenuous person is born otherwise, it does not harm him that he was in slavery and later manumitted. For it is very often decided that manumission does not harm free birth original: "natalibus".

... [Notes on libertines and the definition of manumission].

On libertines.

Libertines are those who are manumitted from a just i.e., legitimate servitude. Manumission, however, is the giving of liberty. For as long as anyone is in slavery, he is subjected to the hand and power, and once manumitted, he is liberated from the master's power. Which matter the law of nations assumed from the beginning, for instance, since by natural law all men were born free, and manumission would not be known when slavery was unknown. But after slavery invaded free-born status by the law of nations, the benefit of manumission followed. And since all men were called by one common name by the law of nations, three kinds of men began to be: the free, and their opposite, slaves, and a third kind, libertines, who ought to have been slaves.

... [Notes on the legal procedures and "three kinds" of manumission].

Manumission proceeds in many ways, whether they are manumitted by sacred offerings in the most holy churches, or by the rod original: "vindicta", or among friends, or by letters, or by testament, or by any other last will. But also in other ways, liberty can accrue to a slave, which were introduced by both the ancients and our constitutions. Slaves are usually manumitted by masters so often that they are even manumitted while passing by, or when the praetor or governor or proconsul goes into the bath or into the theater. However, the status of libertines had been threefold before. For those who were manumitted obtained a greater and just liberty and became Roman citizens; those who obtained a lesser liberty became Latins through the Junian Norban law; those who obtained an inferior status became dediticians original: "dedititiorum" through the Aelian Sentian law.

But the condition of dediticians is indeed the worst from the start.