The high degree of comprehensibility between the signed languages in Trieste (present-day Italy) and Austria is very probably due to their joint history of deaf schools within the Austro-Hungarian Empire. Investigation undertaken in archives in Trieste and Klagenfurt has revealed interesting similarities in the education of deaf children there since the mid-nineteenth century, which may explain present-day affinities. General background information is provided regarding sign language in Italy and Austria, and a detailed description of schools and teaching methodologies, which are the probable source of a historical connection, is then presented.