“Now we don’t like panels or spaces that stretch mountains into a room: here we start painting with stone”. So does Pliny testify to the introduction of a new decorative technique that was to become one of the most popular for paving and decorating imperial buildings, private residences and public facilities: the mosaic. And it is here in Portus, in a late antique thermal facility, that we will discover the long and complex restoration work carried out on a floor mosaic of one of the service areas of the baths. The recovery of an important archaeological asset and the telling of a model of integration that was one of the foundations of Roman society for centuries.