Roman mosaic in Pompeii, Italy, 1st century AD Beware of Dog Discovered in ancient Pompeii Tiny floor tiles in black and white Depict an angry fearsome dog Chained and straining forward Teeth bared, "Cave canem" Spelled out in jet mosaic At the entrance to the Home Of the Tragic Poet, Designed to discourage intruders Before they intrude, To avoid tragedy. And then: Vesuvius. Not even a mad pack Of famished dogs Could keep the poet Safe from that.