The purpose is not specifically recorded, and has been the subject of much commentary. In my opinion, the purpose was to light the church in a way that was primarily decorative. Rose windows had no pictures or words on them and were purely decorative. You will read that stained glass windows were a way of teaching The Bible to illiterate people, but if you go into a medieval church and look up at the windows, you will see that they pretty much all look alike, and can be distinguished best by the words that were painted and fired onto the glass.
I have provided a link to an article on medieval stained glass below. You can look at the pictures there and decide for yourself whether the idea was more educational or more decorative.
It was used more as a teaching tool than propaganda. People couldn't read so the Catholic church ( the only church that there was) would teach the bible through plays. These plays are often called "Passion Plays". Stain glass windows in churches were also used as a teaching tool.
they used a special glass that was hard to find back then
The "new" Gothic cathedral was different from previous churches in its architectural style and grandeur. Two ways in which it stood out were its use of pointed arches and ribbed vaults, which allowed for taller and more spacious interiors, and its large stained glass windows that filled the space with colorful light.
Primitive windows were just holes in a wall. Later, windows were covered with animal hide, cloth, or wood. The Romans were the first to use glass for windows. In Alexandria ca. 100 AD, cast glass windows, albeit with poor optical properties, began to appear. The Romans has stained glass objects but stained glass windows were not made until around 800AD This came from wikipedia http://en.wikipedia.org/wiki/Stained_glass#History http://en.wikipedia.org/wiki/Medieval_stained_glass
The cathedrals that were begun in the middle ages were to done to express the power of God and to display how man was reaching for God through the use of stone and stain glass. Many of them took many years before they were finally finished. The art in the cathedrals and Churches told The Bible stories and the stations of the cross. A huge percentage of the population couldn't read or write so to get the people to understand the stories of the bible they were on the walls and windows of the churches. Passion plays were also done. So, the art and architecture was meant to promote and glorify the church and to show the church as the means for man communicate with God.
It was used more as a teaching tool than propaganda. People couldn't read so the Catholic church ( the only church that there was) would teach the bible through plays. These plays are often called "Passion Plays". Stain glass windows in churches were also used as a teaching tool.
You can try using a razor blade to carefully scrape the stain off the glass surface. Another option is to use a mixture of vinegar and water or a glass cleaner and a non-abrasive sponge to gently scrub the stain. Make sure to rinse the area thoroughly after cleaning.
Lead, coloring, and glass/sand
Glass can be used for windows, to contain liquids.
you use the same glass as you use for winter horticultural, standard, or laminated glass.
Cups, windows and mirrors
Windows. mirrors, bottles.
The current model year Pella windows use glass supplied and manufactured by Cardinal
Windows in houses and other buildings have been used ever since ancient times, in the Babylonian, Assyrian and Pharonic Egyptian Empires, although in those days they were simply open gaps that were covered with either fabric curtains or shutters at night. Even the Romans, who used glassware a lot in tableware, never used glass in their windows as they had not mastered the technique of rolling it to make window panes. The Bronze and Iron Age tribes of Europe did not have windows in their residential huts at all, though they did have small openings in their 'moot halls' to allow light in. Glass first began to be used in windows in late Anglo-Saxon times, mostly in churches, but these could only be constructed using small pieces of glass held together in a framework of lead. This is why stained-glass windows in Mediaeval cathedrals and churches are made up of small pieces with leaden supports in between. During this era, glass in windows was reserved for ecclesiastical use in monasteries, abbeys and churches- even the wealthy upper classes living in castles or fortified manors had open windows that were sealed with wooden shutters at night. The technique of making plate-glass windows by rolling molten glass into flat pieces was not developed until the latter years of King Henry VIII's reign (i.e. 1540's), but it was only the nobility and extremely wealthy who could afford to have these installed- many continued to use the old-style lattice windows, and plate-glass continued to be unusual up until the end of the 17th Century. It was only from around the time of the architect Sir Christopher Wren that plate glass came into widespread use.
Frosted glass spray is not permanent when applied to windows. It can be removed with the use of solvents or scraping.
Since you aren't specific, I will answer with the assumption you are speaking about stained glass windows. In most Cathedrals the stained glass windows tell stories from both the old and new testament. Please remember that when many of the Cathedrals in europe were built most of the people could not read. The pictures in the stained glass windows were something like a picture book. The pictures told a story without the use of words. Both the placement of the windows and the stories they told helped to reinforce Christian beliefs.
Plated glass is a strong rolled and plated glass. It is usually used for mirrors and windows. Sometimes artists use this glass as well.