The Sixteen-Century
The sixteen-century saw glassmakers from Venice and Lorraine establishing glasshouses in England near heavily wooded areas, as the wood was required for the furnaces to produce the glass at the time.
The best know glassmakers of the time were Verzelini from Venice and Carre from Lorraine. Verzelini received a Royal license in 1575 giving him the sole rights to produce Venetian glass at the time. This gave him a monopoly for some time while stopping the importation of foreign glass. The style of glass became known as facon de Venice.
The metal was much improved at the time while giving good clarity when blown thinly and became known as cristallo, however the glass was still prone to decompose on the surface causing crizzling where the glass has a semi opaque appearance and this is also referred to as glass death.

The Seventeenth-Century
There was a rapid decrease in forestland due to the rapid increase in glass production so in in 1615 it was made illegal to use wood in the production of glass. In 1615 Sir Robert Mansell and Sir Edward Zouche obtained the sole right to produce glass in England using coal as the fuel for the furnaces. Sir Robert Mansell was known for completely reorganizing the glass industry throughout England at the time while promoting the mining of coal. There were short periods when it was allowed to import glass form abroad and Sir Robert Mansell took full of advantage of this by importing large quantities from Venice and men to keep up with demand for glass at the time.

The Glass Seller’s Company 1635
The glass seller’s company was formed in 1635 and received its charter from Charles I and after 1664 restructured itself into a very formidable company. Mr John Greene was a member of the company and submitted various designs from 1667 to 1672 while sending the designs to Murano where they produced such items as tumblers and then sent them back to England where the glass items would be sold.
Glassmakers from the Glass Sellers Company were still troubled by glass crizzling and Mr George Ravenscroft who was a retired Venetian merchant set up an experimental glasshouse in Henley On Thames in 1673 and discovered by adding small amounts of lead oxide to the glass reduced crizzling. The correct formula took a few years to perfect the correct amount of lead oxide that needed to be added to the glass.
The manufacture of soda glass became less popular while the production of new flint glass took over which later became known as lead glass.
The Glass Seller’s Company issued a patent giving Ravenscroft’s authorization to produce glass and was distinguished by an applied raven’s head seal. Ravenscroft died in 1681 and his patent was taken over by Mr Harvey Bishopp who took over in the production of glass.