From the Responses of the Same Nicholas, to the Bulgarians, A.D. 866

Response II. Thus ought a man to love him who received him from the sacred font, as a father; indeed, by as much as the spirit is more precious than flesh, because that is a spiritual patronage and adoption according to God, by so much more is a spiritual father to be loved in all things by a spiritual son.

"... Yet there is another gratuitous and holy communion between them, which is not to be called consanguinity, but rather is to be held as spiritual proximity. Whence neither do we judge that there can be any conjugal marriage between them, since indeed neither between those who are sons by nature and those who are sons by adoption do the venerable Roman laws permit marriage to be contracted. Indeed, when the first book of the Institutes was speaking concerning nuptials, among other things it says: 'Between those persons,' etc. ... If, therefore, marriage is not contracted between those whom adoption joins, how much more ought they to cease from carnal cohabitation between themselves whom, through the heavenly sacrament, regeneration of the Holy Spirit binds?"

Nicholas confirms by a certain argument the law already long since enacted by the authority of the Church (cf. the canons of Gregory II); by this argument he does not show whence that law borrows the force of obliging, but he demonstrates the congruence of the same law.

At the same time, however, he indicates that the Caesarean law which establishes the impediment of adoption is approved by the Church, and we rightly suppose that it had long since had force among Christians. But that a law of this sort did not obtain binding force among Christians from the civil power, but from the Church alone, we demonstrate in its place in the treatise, chapter IV; for the present let this observation be enough for us. Nicholas, calling the Roman laws venerable (to which he not rarely appeals in these responses), which are contained in the Justinian law, must be said to attribute no small authority to them. But whence this authority for them in the West, where the Roman empire, now restored, was independent from the Greeks? Certainly the Western peoples, the English, Franks, Germans, and Lombards, were not held by the laws of the Eastern Empire. If you consider the account of civil power alone, those laws were destitute of every force among peoples for whom nothing was common with Justinian and his successors in political rule. Therefore one of two things must be said: either that from the very beginning, when those laws were enacted, by their own force they obliged all Christians, both present and future, both subjects of the Greek empire and those not subjects; or that at some time some supreme power having force in the West approved those laws and procured authority for them among Christians, which supreme power was either that of the Kings of the Franks or that of the Roman Pontiffs. But that first thing is sufficiently absurd; for laws would have had to be enacted by the Greek Emperor for Christians insofar as they are Christians, even if they are not subjects of the Greek empire; but this would have been ridiculous. That other thing is proper and peculiar to the Church. Moreover, the Kings of the Franks, although they permitted Romans to live according to their own laws, nevertheless themselves enacted their own laws, contained in so many capitularies, according to which the missi dominici ought to pronounce law. It remains therefore that we say that the Roman laws at some time began to have force and finally obtained full authority in the West, torn away from the Greek Empire, because the Church approved them. And this indeed we judge to have happened in this way. First, in canonical matter, the Church, retaining or amending those laws insofar as it seemed good to the same, proposed them to Christian peoples, relying on her own authority. But in civil matter, recommending the same laws to societies which were arising, because of the authority in which the Church flourished, she brought it about that first the Frankish Emperors permitted Romans to live according to Roman laws (cf. the Capitular of Lothar given under Eugene II, A.D. 824), and then afterward, Roman wisdom and Roman customs prevailing, the same laws little by little were accepted by all, so far indeed as the morals and customs of diverse nations allowed. Namely, because of the Church's acceptance it came to pass that the Roman laws became venerable; and she, joining together both laws, canon and civil, willed that experts of her own law be thoroughly informed also by knowledge of imperial law. From this you understand why more recent laws, succeeding in civil societies to the ancient law of the Romans, cannot vindicate for themselves that authority which Roman law had borrowed not from the power of the age, but from the Church. For the rest, cf. the cited place.

Response III. According to the law, the consent of those concerning whose conjunctions the matter is being treated suffices. If this consent perhaps has been lacking in the nuptials alone, all other things, even celebrated with coitus itself, are frustrated.

Here you have the amended law of Justinian, who frequently, so that the nuptials of sons of families may be just, requires the consent of those in whose power they are. Institutes, Book I, Title X; Code, Book V, Title IV.

Response XXXIX. Concerning the consanguinity of generations you inquire, that you may clearly know to what women you ought to be joined. But what the laws (Roman laws) sanction here we have already recalled (namely, Response II), and we judge it worth the labor to recall it again summarily. For they say: Therefore it is not lawful for us to lead all women as wives; for we ought to abstain from the nuptials of certain persons. For between those persons who hold the place of parents and children among themselves, nuptials cannot be contracted; as between father and daughter, or grandfather and granddaughter, mother and son, grandmother and grandson, and so on to infinity. Among those persons also who are joined from the transverse degree of cognation, there is a certain similar observance, but not so great (Institutes, Book I, Title on Nuptials). But what the sacred canons and especially the decrees of Zacharias, the supreme prelate, promulgate on this matter, we leave to your bishop to explore for you.

Nicholas needed to cite the sacred canons and the Decrees of the Roman See not only so that in this matter he might protect the authority of the Church, but also lest he suggest to those consulting him a knowledge too defective of the prohibited degrees of consanguinity; for the Roman laws forbidding the nuptials of blood-relatives and affines stop within few degrees.

Response LI. To have two wives at one time neither the very origin of the human condition admits, nor does any law of Christians permit.