Engraved dome in ruby cased glass showing scenes from the history of glass making by Peter Dreiser, 1988. Glassmaking originated in Mesopotamia about 3500-3000 BC, and probably evolved from pottery and metal-lworking traditions. Initially glass was used as a substitute for semi-precious stones and was first used to form glass objects about 2500 BC, when furnaces were developed, which could melt silica. Most of the glassmaking techniques used today were known to the ancient world, with the exception of blowing which was invented about 50 BC, probably in Syria. With the decline of the Roman Empire many skills were lost, though they survived in the Middle East. Venetian glasshouses were highly influential from 1400 to 1700. Later( 1671-1700), George Ravenscroft invented lead glass which could be cut and engraved. The second half of the 19th century was a period of great inventiveness especially in the development or coloured glass.