A fragile glass vessel survives the fall of Rome, wars, plagues, and Renaissance popes, only to be smashed in the British Museum in 1845 by a drunk university student who picked up a nearby sculpture and threw it. This episode traces the full life cycle of the Portland Vase, the most famous piece of Roman cameo glass in existence. We start with how it was made in the early empire, only decades after glassblowing itself was invented: a bubble of molten blue glass dipped into molten white, cooled without tearing apart despite different thermal expansion rates, then carved by a gem cutter over what was likely two years of labor.

The carved scenes have never been decoded with certainty. We walk through the mythological readings, including the marriage of Peleus and Thetis, and the political theory that the vase was propaganda for Octavian, with ...