British Museum, London 2005.
"The Portland Vase is a first century BC Roman cameo glass vase, which served as an inspiration to many glass and porcelain makers from about the beginning of the 18th Century onwards. Since 1945 the vase has belonged to the British Museum in London (reference - GR 1945.9-27.1 (Gems 4036) ; on display in Room 70, Rome: City & Empire).
The vase is about 25 centimetres high and 56 in circumference. It is made of violet-blue glass, and surrounded with a single continuous white glass cameo depicting seven figures (humans and gods).
On the bottom was a cameo-glass disc, also in blue and white, showing a head, presumed to be of Paris or Priam on the basis of the Phrygian cap it wears. This roundel clearly does not belong to the vase, and has been displayed separately since 1845. It may have been added to mend a break in antiquity or after, or the result of a conversion from an original amphora form (paralleled by a similar blue-glass cameo vessel from Pompeii) - it was definitely attached to the bottom from at least 1826."