Glass itself is not a Phoenician invention: the earliest archaeological evidence of glassmaking comes from Mesopotamia and, above all, Egypt, with opaque glass beads dating back to the fourth millennium BC. What is genuinely Phoenician is a much later, decisive technical innovation: around the 1st century BC, artisans of the Syro-Palestinian coast (especially in Tyre and Sidon) invent the technique of glassblowing via a hollow tube, allowing a practically unlimited number of shapes to be created much more quickly and cheaply than previous core-forming methods. Decades earlier, around 1000 BC, artisans of Sidon and Tyre had already discovered that adding antimony to the mixture markedly increased glass transparency, transforming a traditionally opaque material into a transparent luxury product. The combination of both innovations — transparency and blowing — drove glass workshops in every Phoenician city, whose products were exported throughout the Mediterranean and, later, adopted and popularized by the Romans; the glassmaker Ennion of Sidon, active in the Tiberian-Claudian period, is one of the best-documented masters of the decorative mold-blowing technique.