
glass industry north of the Alps takes off (since 1100 A.D.)
From about 1100, glass production north of the Alps took off again. This comprised mainly utensils, drinking vessels and bottles, but window glass was also manufactured. The crown glass method was rediscovered, and the cylinder glass method (re?)invented.
Window glass was an extremely precious and valuable product, and therefore primarily used in churches, monasteries and several castles.