The Romans often paved the floors of their houses and public buildings. The most magnificent and spectacular of these floors used a technique known as opus tessellatum. Other common methods of paving were opus signinum, made of lime and a mixture of ground stone and ceramic, or opus sectile, made with fragments of marble.
Here we have a marble tesserae paving with the inscription AVE SALVE, a welcome greeting. It would have been part of the interior threshold of a door in a Tarraco domus.