From the Epistle of Paschal II, to Bonus Senior, Bishop of Reggio, A.D. 1100-15

Chapter I. After a spiritual son or daughter has been received from the font, those who have been born from the co-father or co-mother cannot be joined in matrimony (with that son or daughter), because the laws of the age prohibit those not emancipated from being coupled to adoptive persons.

He says "after"; for those born before were not prohibited. Cf. the decree of Alexander III below.

Chapter II. After the death of the wife, no authority or reason seems to prohibit being coupled in marriage with the co-mother of the wife of the surviving husband. For neither is cognation of spirit compared to cognation of flesh, nor through union of flesh is there a crossing over to union of spirit.

Cf. the reason shown by Canon XLVII of the Council of Tribur, A.D. 895.

Chapter III. Further, as for the spouses of two female cousins, although at diverse times, that the one marry one man after the death of the other: public honesty itself, apart from canonical authority, contradicts it. And your prudence knows that one must abstain from the blood-relatives of the wife just as from the blood-relatives of the husband.

It was the third degree of affinity. Cf. De Iustis, On Matrimonial Dispensations, concerning Affinities.