From Gugliielmo Ferrero, The Women of the Caesars

Two thousand years ago, the remains of Rome’s deceased slaves, freed men and women, and poor citizens were placed in columbaria (literally, “dovecotes”) in underground chambers. As depicted in this century-old painting by an unknown artist, mourners would gather in the funerary chamber to deposit a cinerary urn or small sarcophagus in one of the tomb’s semi-circular niches. On the wall near the niche, the mourners would sometimes affix a stone epitaph recording the name, lifespan and virtues of the deceased. They would also often leave offerings in the burial chamber.