The Lycurgus Cup

This remarkable cup depicts an episode from the legend of Lycurgus, King of the Thracians. After angering the god Dionysus by driving him to the depths of the sea, Lycurgus attacked his maenads, one of whom - Ambrosia - was saved by Mother Earth, who transformed her into a vine. The scene shows Lycurgus struggling to escape from her clinging tendrils. Tiny amounts of colloidal gold and silver in the glass give it unusual properties; it appears opaque and pea-green in reflected light, but it becomes deep wine red if held up to the light. It was probably originally used as a lamp. It is the sole complete surviving example of this type of glass, technically known as dichroic.