Flexible Glass

Flexible glass, or vitrum flexile, is the name given to a lost invention said to date from the reign of the Roman emperor Tiberius, an account that ancient sources themselves and modern historians treat as almost certainly a legend. According to the story, recorded by both Petronius and Pliny the Elder, an inventor presented Tiberius with an unbreakable glass bowl that dented rather than shattered when dropped and could be hammered back into shape, and the emperor reportedly had the man executed rather than let the invention become known, possibly to protect the value of glass, gold or silver. Pliny himself noted that the tale was more widely repeated than well verified, and the modern historian Robert Jacobus Forbes suggested the story may have grown out of a real but far less dramatic technique for bending glass into curved shapes such as vessel handles.