 Iconographic research is unhelpful for this purpose because the motifs derive from a traditional repertoire, which was used largely without variation over a long period of time.Motifs from daily life are more helpful, however, since some of them depict datable building work such as the Capitoline Temple, which was built in AD 82 and is depicted on a relief from the Louvre Museum, providing a "terminus ante quem" for that tile.A better aid to dating is the quality of the clay.