Rights in the Family
Appendix 3. (1140).
This intrinsic reason [for impeding marriage between close relatives] does great honour to the Church which extended the impediment of consanguinity to cousins of the fourth degree. Roman laws did no more than forbid marriage to first cousins. This means that amongst the Romans civil society prevailed over domestic society. The situation was reversed by the Church when she undertook to safeguard the family against the tyranny of the State. Moreover, the increased holiness of Christian marriage brought in its wake greater reserve and caution about contracting marriage. Dumoulin is fantasising when he wants us to believe that such an extension of degrees arose from an error of interpretation of Roman law which understood the fourth degree as cousins-german, while the Church understood it as nephews of cousins-german.
Nevertheless, despite the nebulous quality of any consideration that would erroneously suppose such ignorance in the entire religious and political world (which was never without persons who cultivated the study of Roman law), we shall add a factual observation intended to free the Church from such an inept calumny.
It was political authority, inspired by religion, which first prohibited marriage between cousins towards the end of the fourth century. St. Ambrose (Ep. 60, ad Paternam), speaking of this law of Theodosius writes: `The Emperor Theodosius forbade siblings, and cousins on the part of the father and the mother, to come together in marriage. He established very severe penalties for anyone who dared to contaminate the holy bonds amongst siblings.' St. Augustine, praising the same law, says: `Who can doubt that it is more decent at this time to forbid even the marriage of cousins on the mother's side?' (The City of God, 15: 16). It is clear that both political authority and the Fathers knew perfectly well the limits of the ancient law, which they did not extend through the error supposed by Dumoulin. Nevertheless (and this is scarcely credible) this malicious fantasy was eagerly embraced by the sophists of the last century who were prepared to believe even the most idiotic things provided they were harmful to the Church. As a result, the Napoleonic Code did away with the third and fourth degrees of relationship (art. 163) despite the ecclesiastical laws.