The medieval West generated a great glass revolution (noted a couple of days ago.) Why? Why was the West peculiar in glass?
Recall the five uses of glass.
1. Decorative glassware: Eurasia but not the Americas or Africa.
This is a common pattern. Eurasia had more technologies than the Rest. The best-known explanation is Jared Diamond’s ingenious idea that Eurasia’s geography – larger, a head start with agriculture—gave it advantage. But geography is opportunity, not response; it is structure, not agency. All technical advances are due in part to cognitive upgrading or rationalization, and this must be so with glass production.
2. Vessels: the Middle East and the West – especially wineglasses in ancient Rome and medieval Venice.
This is somewhat mysterious. Perhaps people enjoyed wine from glass rather than metal or pottery vessels. Perhaps as in China and Japan tea was more suited to pottery. (And yet in Turkey today tea is served in glasses.)
3. Glazed windows: little developed in Asia or Southern Europe, highly developed in Northern Europe after 1000. A great window revolution saw window glass spreading, particularly in churches and cathedrals, later in houses. (more)
Alternative window coverings were paper (China, Korea, Japan) or grillwork (useful in hot regions such as the Middle East). No doubt climate had something to do with it: cool, overcast NW Europe needed light to enter and heat to stay. Absence of earthquakes meant paper was unnecessary. The Church played a key role: compare the large glazed windows of European churches to the windowless or small-windowed temples of antiquity, Hinduism, or Buddhism.
In NW Europe, there were not the courtyard houses common in China, the Middle East, or the Mediterranean. Such houses presented a blank wall to the outside. There is no need for glazed windows. European houses were more open to the outside world. A need for glazed windows arises.
4. Mirrors: largely Western Europe from the Renaissance (elsewhere polished metal served the same purpose).
Since Venice was the core of glass production, I assume the expertise it built was the main cause.
5. Lenses, prisms, and spectacles: Western Europe. Spectacles spread from about 1280.
Quite why medieval Italy invented spectacles is unclear. It indicates a level of inventiveness not associated with the “backward” middle ages.
All five: only the West–by the remarkably early date of 1300.
I do not have a single answer as to why there was a glass revolution. It seems to bring together several influences: geographic, religious, and most importantly a process of rationalization.