Incestuous marriages in late C arolingian R avenna: the causa D eusdedit (878–81)

During the ninth century and especially after L othar II 's divorce, the C arolingian reformers turned their attention to the definition of legitimate C hristian marriage, promoting and spreading precise rules to discipline the marital strategies of aristocracies in the C arolingian world. L egislation against incestuous marriages became progressively more radical, extending the scope of incest not only to consanguinity, but also to affinity and spiritual kinship. This article examines the effects of the new prescriptions in late C arolingian R avenna through an analysis of P ope J ohn VIII 's letters concerning the so‐called causa D eusdedit , a controversial trial for incestuous marriage.