In the late 1500's, canon law proclaimed that those who were deaf only but able to speak could be regarded legally as persons able to inherit, enter into contracts, and assume legal obligations. This was particularly relevant in cases where noble titles and great estates were involved. Many of the noble and royal houses of Europe, through marriages among themselves and other inbreeding practices, have to this day perpetuated a number of recessive genetic anomalies, among them hemophilia and congenital deafness.
