document — Palmieri, On Christian Marriage
From the Roman Synod of Eugene II, A.D. 826
Canon XXIX. Women who have taken a religious habit or veil under pretext of religiousness, when they were able to have husbands, are not thereafter permitted to be associated to men; but, choosing monasteries, let them live regularly, or in houses chastely observe the habit they have taken. But those found base are to be corrected by the providence of the Bishop.
Cf. the Decrees of Innocent I, above.
Canon XXXVI. It is lawful for no one, except for the cause of fornication, to leave a wife who has been taken, and then to couple another; otherwise it is fitting that the transgressor be associated to the former marriage.
Namely, if he has attempted to lead another, existing as a transgressor, let him return to the former wife, from whom he was separated. It proceeds:
But if a husband and wife have consented between themselves to depart for the sake of religious life alone, by no means let it be done without the knowledge of the bishop, so that, by him having provided separately, they may be established in a place. For if the wife is unwilling, or the other of them, even for such a thing (that is, religious life), the marriage is not dissolved.
Namely, separation in this hypothesis is forbidden.
Canon XXXVII. It is lawful for no one to have two wives at one time, or a wife and a concubine ... For just as Christ observes the Church chaste, so the husband ought to guard chaste marriage.
Canon XXXVIII. Let no one dare to couple to himself in marriage a female cousin, a niece, a stepmother, a brother's wife, or even someone from his own cognation, or her whom a cognate had. But if anyone has come together in such a nefarious marriage and has remained in it, let him know that by apostolic authority he is bound by the bond of anathema, and let no priest grant him communion. But if, having been converted and divided from the illicit copulation, he has been so, let him be subjected to worthy penance, as the priest of the place shall have considered.
Cf. the canons of Gregory II in the Roman Council.