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.
Stained glass
Probably the earliest scheme of stained glass windows that was created during the Renaissance was that for Florence Cathedral, devised by Lorenzo Ghiberti. The scheme includes three ocular windows for the dome and three for the facade which were designed from 1405 to 1445 by several of the most renowned artists of this period: Ghiberti, Donatello, Uccello and Andrea del Castagno. Each major ocular window contains a single picture drawn from the Life of Christ or the Life of the Virgin Mary, surrounded by a wide floral border, with two smaller facade windows by Ghiberti showing the martyred deacons, St Stephen and St Lawrence. One of the cupola windows has since been lost, and that by Donatello has lost nearly all of its painted details.