The Lycurgus Cup; 4th-century, Roman glass cage cup. Made of a dichroic glass, which shows a different colour depending on whether or not light is passing through it; red when lit from behind and green when lit from in front. It is the only complete Roman glass object made from this type of glass. The cup is also a very rare example of a complete Roman cage-cup, or diatretum. It named after King Lycurgus