The Institutes of Justinian

Let us now examine the modes in which persons dependent on a superior become independent. How slaves are freed from the power of their masters can be gathered from what has already been said respecting their manumission. Children under paternal power become independent at the parent’s death, subject, however, to the following distinction. The death of a father always releases his sons and daughters from dependence; the death of a grandfather releases his grandchildren from dependence only provided that it does not subject them to the power of their father.