History of glass
The history of glass-making dates back to at least 3600 years ago in Mesopotamia. However, they may have been producing second-rate copies of glass objects from Egypt, where this complex craft originated. Other archaeological evidence suggests that the first true glass was made in coastal north Syria, Mesopotamia or Egypt. The earliest known glass objects, of the mid second millennium BC, were beads, perhaps initially created as the accidental by-products of metal-working (slags) or during the production of faience, a pre-glass vitreous material made by a process similar to glazing. Glass products remained a luxury until the disasters that overtook the late Bronze Age civilizations seemingly brought glass-making to a halt.
Cranberry glass
The origins of cranberry glass making are unknown, but many historians believe a form of this glass was first made in the late Roman Empire. This is evidenced by the British Museum's collection Lycurgus Cup, a 4th-century Roman glass cage cup made of a dichroic glass, which shows a different colour depending on whether light is passing through it or reflecting from it; red (gold salts) when lit from behind and green (silver salts) when lit from in front.