Domus de janas are prehistoric burial structures consisting of rock-cut tombs. They are found throughout the Mediterranean basin, but particularly in Sardinia where they can be seen throughout the island either isolated or in large concentrations often consisting of more than 40 tombs. In the Sardinian language the term domus de janas means house of fairies or witches, but they are also known as forrus or forreddus. Starting from the Final Neolithic to the Early Bronze Age, these structures characterized all pre-Nuragic cultures. To the culture called San Michele di Ozieri dates the construction of the two domus de janas in the Is Pruinis territory, excavated on the Is Baccas mountain. The caves present a quadrangular plan, preceded by an atrium and provided with three loculi raised from the floor and of a width suitable to receive several burials, according to architectural schemes that reproduce the structure of dwellings and sanctuaries. Of particular interest are the small columns in front of the burial niches that indicate clear symbolic features peculiar to Mediterranean mythology. It is likely that within the tombs the ritual of incubation was practiced, a practice that consisted of sleeping at the tombs of ancestors in anticipation of revelatory dreams, also related to medico-sacral practices. In the Chalcolithic and Eneolithic periods, the presence of the Monte Claro and Bell Jar Cultures in the Sulcis territory involved the occupation of the same burial spaces, the deceased were then interred in the same caves within which numerous ceramics related to these cultures have been found.
