The British Museum date it between AD 1 and AD 25 - collection database ("5-25 AD" per the Highlights section, and Williams in 2009); a date some time between 30 BC and 20 BC was suggested in 1990, following research by William Gudenrath, Kenneth Painter and David Whitehouse, Director of the Corning Museum of Glass, Journal of Glass Studies, Vol 32 1990.
