From the Epistle of the Same, to Theodore, Bishop of Pavia

Response I. You took care to ask us whether it is lawful for a son whose father received another man's daughter from sacred baptism, that is, as spiritual father (perhaps "the spiritual father"), to take in marriage the daughter of the same (namely, other) father, which it is cruel to say, which you disclosed had happened enormously among you (namely, whether the son of him who received some woman from the sacred font could lead this woman as wife). But your fraternity well knows what the Lord commands through Moses, saying: You shall not reveal the shame of your father; for the daughter of your father is your shame. For the shame is said not to be revealed when it is commanded that one abstain from one's own consanguinity. Much more therefore does it befit us, with every occasion or argument set aside, to beware entirely, under excessive detestation, of the daughter of our spiritual father.

Others read thus: "It is not fitting at any time to hand over in marriage to one's own man (perhaps, son) the daughter whom one has received from the sacred font; because in divine knowledge they are found to be full siblings (cf. above, the cited sayings of Zacharias from the Vatican codex). If anyone, mixed in such a crime, has not at all restrained the reins of luxury, he will be abominated by the Catholic Church. But if he has been converted, after separation let him perform penance for seven years. Let this condition be for those aware, together with the author: that is, together with the cooperators and consenters, let him do penance."

Thus also much later Paschal II responded (cf. below at the year 1000-115), but it later seems to have been abrogated by Alexander III. Compare below, in the collection of canons ascribed to him, under the title concerning joining children, etc.

Response II. But concerning the children who are proved to have been born from them: you asked whether it is lawful for them to be coupled in marriage or not. But why should these be prohibited from marriage, or be compelled to do penance for this sort of thing, since they are proved to be without condemnation from this, because neither will the father sustain torments for the son, nor the son for the father?

Response III. But concerning that chapter which you intimated to us, in what generation one ought to be joined from one's own kinship, because others wish to vindicate for themselves this which was directed by St. Gregory to be observed among the nation of the Angles down to the fourth progeny. But that pious Father himself imposed certain light things on the rude and those newly coming to Christ, lest, if he had imposed graver things, they would bear them harshly and, being a harsh race, would utterly cast aside all the things which they had received. But we wish that the people committed to you should observe not as those who newly received Christ ought to observe, but as those who have been nourished from their cradles in the holy Catholic Church: that, when they have indeed known themselves to be of their own kinship, they should by all means abstain; just as the holy Catholic and apostolic Roman Church of God holds and preaches this.

Cf. Siricius, Decree VI, from the epistle to Himerius, above.

The tradition of the Roman Church, to which he appeals, is that certain one which Gregory III, above, and Gregory the Great in the epistle to Felix, above, expressed.

You see by this response of Zacharias that the authenticity of this epistle of Gregory the Great to Felix, about which Coustant doubted, is confirmed.