Christ Crowning the Martyrs Peter and Paul

Christ Crowning the Martyrs Peter and Paul. Gold glass fragment from Rome, 4th century C.E. ©The Trustees of the British Museum.

Gold-glasses—objects with gold foil ornament sandwiched between two fused layers of glass—are primarily found in catacombs, the underground galleries where early Christian and Jewish communities buried their dead. Roman glass-makers often applied the gold as foil then worked the design by scratching the gold with a stylus. The top layer of glass was then fused in a kiln.

Often they were set in plaster surrounding a niche used for burying the dead.  Some think that gold-glasses were made as roundels to be used exclusively to decorate graves but many gold glass fragments have foot rings and a few even retain parts of the wall so they may also be recycled from the bases of broken bowls. After the 4th century, glass making declined in most parts of the Roman Empire and many of the more elaborate techniques were abandoned.