Description:Le gemme romane e post-antiche del Museo Archeologico Nazionale di Cagliari provides a catalogue raisonne of around 200 engraved gems from the Roman and post-antique periods currently or formerly preserved in the National Archaeological Museum of Cagliari (Sardinia, Italy). Through archival and bibliographic research, it was possible to determine the processes of acquisition and the historical-antiquarian collection to which they belong (Spano, Timon and Gouin). Their acquisition took place through donations or through purchase by the museum between the second half of the 19th century and the beginning of the 20th, defining the historical stages in the formation of the Museum's collection. The study of this series of gems arose from the desire to discover and define the significant information potentially inherent to this artistic category, which lies between the public and private spheres. It also highlights the importance of the most conspicuous glyptic collection of the island, which can offer a socio-cultural, religious and political overview of the people of Roman Sardinia.