From the Epistle of the Same Nicholas I, to the Bishops of Germany Who Had Assembled at the Council of Mainz, A.D. 863

Since, as you report, it was proved in your council by truth-speaking witnesses that Abbo had presumed to accept a wife contrary to the sanctions of the holy canons, and had coupled her to himself even in the fourth generation, we sanction and by apostolic promulgation decree that the coupling of this ill-omened marriage be dissolved in every way, because it is shown and known to be of his own consanguinity and cognation. And, with you asking this, we establish that it is lawful for no Christian to accept a wife from his own consanguinity or cognation so long as the generation is remembered, known, or retained in memory. But we rejoice and praise the observance of your diligence, because in this matter you hold that the decrees of our blessed predecessors, Pontiffs Gregory and Zacharias, have been observed up to now in your parishes, as you have brought forward in your letters. For you have said: In what generation are the faithful joined to each other? But we do not define the number of generations in this matter, but, as we reported above, we admonish that it be observed without hesitation.

Cf. what we disputed after the epistles of Gregory the Great. Here also Nicholas abstains from a clear determination of the degrees of consanguinity and affinity, but uses a general formula. A little before, the German Bishops in the Council of Mainz under Rabanus had invalidated marriages only up to the fourth degree, and the same knew, as it is lawful to gather from this epistle of Nicholas, the decrees of Gregory II and Zacharias. Now the German Bishops, perhaps doubtful whether those decrees had been rightly understood, ask Nicholas in what generation marriages are lawful; the Pontiff answers that as long as certain persons know themselves to be of the same cognation, they cannot be coupled in marriage.

Nevertheless, in the collection of Capitularies of Benedict the Levite, prepared at that age, Book III, n. 432, there exists a decree which is also cited in his canons by Isaac of Langres and by Herard, Archbishop of Tours, in his capitula about A.D. 858, having thus: "Let none of the faithful, up to the line of affinity, that is, up to the seventh progeny, lead his blood-relative as wife, or in any way pollute her with the stain of incest." Yet in the same age, as Hincmar of Reims reports, Epistle XXII, a certain noble man named Stephen excused himself from consummating marriage with her whose blood-relative he had previously violated, because, as he said, he had heard that those pertaining to each other from the fourth kind and onward (that is, below it) could not be coupled. For which reason, in the Council of Worms in the year 868, Canon 32, the Fathers were still speaking with Nicholas; see below. Cf. the doctrine of Peter Damian which we give below under the Roman Council of Alexander II. Cf. besides the response of John VIII to Airard below, and at the same time the words of the second Synod of Douzy, A.D. 874, below.

The Pontiff proceeds, passing to other matters. And concerning parricides and fratricides, after suitable penance has been prescribed, he decrees: "Let them not be separated from their wives if they have them; but if they do not have them and have not been able to contain themselves, let them accept legitimate women in marriage, lest they appear to fall into the abyss of fornication."

Cf. what was said at Response VI of Leo to Rusticus. Nicholas permits parricides and fratricides, after penance has been completed, to enter nuptials.

Again: "If anyone has fornicated with two (sisters?) or with those persons concerning whom Sacred Scripture forbids, if he has done worthy penance and yet has preferred not to sustain continence, let it be lawful to accept a legitimate wife in marriage. Similarly also let the woman who has fallen by such a crime fulfill this, so that she not be led down to the chaos of fornication."

The Pontiff relaxes the law prohibiting marriage because of the crime of incest, and requires only that worthy penance be done concerning that crime. But cf. his following Response I to Harduic, Archbishop of Besancon.

Likewise: "If anyone has fornicated with a spiritual mother, he is struck, as you know, by blows of anathema. In similar manner we promulgate that he also is to be struck who has perpetrated the crime of fornication with her whom he received from the sacred font of baptism, or with her whom he held before the bishop when she was anointed with sacred chrism; nevertheless, if he has a legitimate wife, let him not dismiss her."

The Pontiff is not dealing with marriage which is attempted with persons of this sort, but with the sin of fornication, which is graver with persons joined by spiritual cognation.