By concentrating on the religious conceptions underlying marriage in the Ca
tholic Church and on the relations between theology and canon law, we can a
ssess the consequences of this type of marriage on the limits of the kin gr
oups defined through canon law's matrimonial prohibitions. For this structu
ral interpretation, methodological considerations are worked out in order t
o break the stalemate to which predominant views, claiming to be sociologic
al, have led in the study of European kinship.