History of glass
Glass remained a luxury material, and the disasters that overtook Late Bronze Age civilizations seem to have brought glass-making to a halt. It picked up again in its former sites, Syria and Cyprus, in the 9th century BC, when the techniques for making colorless glass were discovered. The first glassmaking "manual" dates back to ca. 650 BC. Instructions on how to make glass are contained in cuneiform tablets discovered in the library of the Assyrian king Ashurbanipal. In Egypt glass-making did not revive until it was reintroduced in Ptolemaic Alexandria. Core-formed vessels and beads were still widely produced, but other techniques came to the fore with experimentation and technological advancements. During the Hellenistic period many new techniques of glass production were introduced and glass began to be used to make larger pieces, notably table wares. Techniques developed during this period include 'slumping' viscous (but not fully molten) glass over a mould in order to form a dish and 'millefiori' (meaning 'thousand flowers') technique, where canes of multicolored glass were sliced and the slices arranged together and fused in a mould to create a mosaic-like effect. It was also during this period that colorless or decolored glass began to be prized and methods for achieving this effect were investigated more fully.
Bohemian glass
Bohemian glass-workers discovered potash combined with chalk created a clear colourless glass that was more stable than glass from Italy. In the 16th century the term Bohemian crystal was used for the first time to distinguish its qualities from glass made elsewhere. This glass contained no lead as is commonly suspected. This Czech glass could be cut with a wheel. In addition, resources such as wood for firing the kilns and for burning down to ashes were used to create potash. There were also copious amounts of limestone and silica. In the 17th century, Caspar Lehmann, gem cutter to Emperor Rudolf II in Prague, adapted to glass the technique of gem engraving with copper and bronze wheels. During the era, the Czech lands became the dominant producer of decorative glassware and the local manufacture of glass earned international reputation in high Baroque style from 1685 to 1750.