Chapter — Slater, Manual of Moral Theology
Chapter XIII. Revalidation of Marriage
WHEN marriage has been contracted invalidly the ordinary thing to do is to secure its being contracted validly, if this is possible. It may have been invalid on account of clandestinity, or for want of consent, or because there was some diriment impediment between the parties.
When the marriage was invalid on account of clandestinity, it must be revalidated by supplying the defect and contracting marriage anew before the parish priest and two witnesses. If the invalidity of the first marriage was known publicly, the second must be publicly solemnized; otherwise it will be sufficient to contract it in private (Can. 1137).
p. ii, 246
When the first marriage was invalid for want of consent of both the contracting parties, the only way of revalidating it is by both renewing their consent. This, again, should be done publicly if the invalidity of the former marriage was matter of public knowledge; in other cases it will be sufficient to renew consent in private. When the former marriage was invalid for want of consent of only one of the parties, it will be sufficient if this party after becoming acquainted with its invalidity freely renews his consent if the consent of the other party still persists. This may be done validly not only by express word of mouth, but by living together as man and wife, and exhibiting the ordinary signs of matrimonial union (Can, 1136).
p. ii, 246
When the first marriage was invalid on account of some diriment impediment between the parties, the first thing to do is to remove the obstacle to marriage by obtaining a dispensation from the impediment and duly executing it. If both the parties were aware of the impediment, they must renew their consent either in public or in private, according as the nullity of the marriage was publicly known or not (Can. 1135).
This renewal of consent is a new act of the will consenting to the marriage, with knowledge of its previous invalidity, and is necessary for validity by ecclesiastical law (Can. 1133, 1134).
If the impediment is occult and not known to one of the parties, it is sufficient for the party who knows of the impediment to renew his consent privately and in secret, provided that the consent given by the other party still persists (Can. 1135, sec. 3). ‘Sometimes not even this can be done, and in such cases of special difficulty recourse may be had to a dispensation in radice, as it is called, by which the Holy See sometimes revalidates a marriage without any renewal of consent by the parties. By a dispensation in radice the diriment impediment which existed is removed, the marriage is validly contracted by the consent which was given in the former marriage and which still subsists, and the children, if any have been born, are legitimized as if the former marriage had been valid. By a fiction of law, the former marriage is held to be valid and to have all the effects of a valid marriage.
It is obvious that to enable the Church to do this the impediment must be merely of ecclesiastical origin, and so capable of being removed by the Church; the consent given in the former marriage must of itself be valid and capable of effecting a real marriage except for the impediment, and, moreover, the consent of the parties must still persist at the time when the dispensation is given, otherwise true marriage can never exist between the parties. If these conditions are fulfilled by a dispensation in radice without any renewal of consent, the parties will be truly married, and the effects of marriage will date from the first contract, though it was invalid (Can. 1138-1141).
p. ii, 246–247