A type of luxury glass vessel made in the Late Roman period, beginning in the 4th century CE.  A cage cup consist of an inner beaker and an outer shell or “cage” of decoration that stands out from the body of the cup. About fifty cage cups have survived, mostly in fragmentary condition. Video here. Web resource here.

The Cologne Cage Cup. Glass. First half of the 4th century CE. Römisch-Germanisches Museum, Cologne, Germany.