In the 15th Century, Venice had become the major producer of glassware in Europe. So highly esteemed were the Venetian glass makers, that they were forbidden to leave the Island of Murano, lest their precious trade secrets be imparted to others.
However, it was to be another two centuries later in 1676, an Englishman named George Ravenscroft discovered that by adding lead oxide to the glass composition, a far more brilliant, sparkling glass could be produced than had ever been made before. Lead crystal has now been born.