Stained glass windows within the majestic architectural wonders of European Catholic churches and cathedrals were are amazingly beautiful works of art that were devised as decorative structural devices only partway; they were also communicative devices of Vatican propaganda to instruct a mostly illiterate audience who had no idea whether the priests who were reading from the Holy Bible were telling them the whole truth or not. Illustration was the name of the game and propaganda was the war by which these amazing works of colorful art thrived. The Catholic church’s stained glass illustrations corrupt the positive aspects of the Bible and, especially, the teachings of Jesus Christ.
Stained glass began during the Roman Empire in their infamous public bathhouses, of all places. The stained glass windows allowed light to peek through without the disadvantage of losing the heat from inside. Stained glass to tell stories from the Bible most likely began inside the Hagia Sophia cathedral instituted by Christianity’s second most famous convert, Constantine. (Saul/Paul must surely be the most famous convert.) A stained glass representation inside a cathedral in Germany dates back to 1095 and is thought to be the oldest known piece of stained glass artwork from a Christian church.
If you really want to cast credit or blame to a civilization re: stained glass, then direct your venom or prayers to the Goths. Byzantine architecture disallowed large windows due to the necessity to keep up the heavy weight of the roofs of cathedrals built during this period. Gothic architecture introduced the flying buttress and other supports that lessened the need for downplaying windows. Large windows could be exploited by the Catholic Church to instill the very same allegiance to poverty that so pissed off Friedrich Nietzsche. The Uberman that Nietzsche proposed should not be looked upon as the Nazi Mel Gibson of Hitler’s heated and unsavory fantasia, but rather as a throwback to the strong gods of pagan religions. The Catholic Church saw a delicious advantage in convincing illiterate followers of the value of being poor and meek and took great pains to reach as many as possible. Lacking the ability or affordability of reading the Bible, those great stained glass parables that repeated the stories of suffering as a means to salvation worked much better than even allowing the faithful to read.
Or taking the time to educate them to read.
Part and parcel of the Reformation was a reaction again using stained glass to lead the devoted to faithful allegiance. This was partly due to the fact that the Reformation coincided with the invention and marketing of the printing press. Lutherans no longer had to rely on stained glass to follow the stories of Job or Jonah; they could read them with a copy of their own Bible. As the printing press made copies of the Bible more omnipresent, the rate of literacy increased. As the rate of literacy increased, the value of stained glass pictorial illustration of Biblical stories decreased.