From the Council of Troia, Urban II Presiding, A.D. 1093

When the matter had been treated concerning certain persons coupled within the line of consanguinity, at last, with all consenting, this capitulum concerning them was promulgated.

Let the bishops whose diocesans they are convene them up to Pentecost by a threefold summons. Then if two or three men have confirmed the consanguinity by oath, or they themselves perhaps have confessed, let the marriages be dissolved. But if neither has happened, let the bishops adjure them by the baptism of Christ, by the faith of Christ, by the judgment of Christ, in true obedience, that they openly make known whether, as fame has it, they recognize themselves as blood-relatives. If they have denied it, they are to be left to themselves, yet in such a way that, if they have something else in conscience, they should know themselves separated from the thresholds of the Church, from the Body and Blood of the Lord, and from the communion of the faithful, and made infamous, until they desist from the crime of incest. If they have segregated themselves by the judgment of the bishops (namely after an incestuous union), if they are young, they are not prohibited from contracting other marriages.

Cf. the responses of Nicholas I as to the last part of this decree.