"Behold, the tabernacle of God is among men, and He shall dwell among them, and they shall be His people, and God Himself shall be among them."
The purpose of building Gothic cathedrals was to build a temple worthy of God. In the twelfth century, bishops became independent of the secular power and took their destiny, and that of the Church, into their own hands. The growing power and prestige of the bishops combined with the architectural development of the flying buttress and rib vaulting enabled the building of the great Gothic Cathedrals. Stained glass work attained its epiphany in the windows of these Gothic cathedrals. The stained glass windows constructed during the thirteenth century are considered some of the finest examples of this art form.
The extensive use of stained glass windows could not have taken place without the invention of rib vault architecture. Rib vault architecture allowed the weight of the stone roof to be carried by the visible ribs. The webbing between the ribs was lighter placing less stress on the lower portion of the building. This meant that the walls could be opened to let in sunlight and illuminate the interior of the church with God's own light. The development of the flying buttress to support the walls, at the points of stress, meant that the walls of a cathedral could almost literally become walls of light. All parts of the cathedral architecture had their basis in the scriptures. Likewise, the significance of the light passing through the windows can also be found in the Bible.
The references to light in the Bible are numerous. The purpose of the windows in a cathedral was to tie together the earth and the heavens, the supernatural and the natural world. Beginning with the book of Genesis, God created light and saw that it was good. Jesus Christ Himself says "I am the light of the world; he who follows Me shall not walk in the darkness, but shall have the light ...