Why a piece of ancient pot and a scrap of Virgil’s poetry speak to us down the ages

A slave empties wine from an amphora, in a detail from an ancient Roman sarcophagus in the National Museum of Beirut. Photograph: Sean Kingsley

There are moments when an ancient object emerges from the soil and seems, for a second, to close the gap between you and the deep and slumbering past. Then, almost as soon as a picture has shifted into bright focus, the illusion of connection passes: one is left with the same old sensation of puzzle, of seeing a long-distant world indistinctly and partially, as if through a misted-up pane of glass.

This week, one of those moments of brief and magical clarity arrived in the form of an unassuming shard of Roman terracotta, 6cm by 8cm, found in Andalucía’s Guadalquivir valley.