Why Do Churches Have Stained Glass Windows?

Stained glass windows play games with the light in many modern churches. The tradition of making those windows goes back a long way. As early as the fourth century, colored glass was used to ornament church windows, though it was not until the 12th century that making stained glass became an art form like sculpture or painting. Yet stained glass was not just a decoration. It was a way of communicating scenes and episodes from the Bible to everybody -- including those unable to read.

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In April of 1144, Louis VI of France entered a new cathedral, the royal abbey of St. Denis. What he found was a building filled with daring architectural innovations. St. Denis was one of the first of many churches to be constructed in a new fashion, later called Gothic. Before the Gothic style of architecture became popular, many buildings were made in the Romanesque style. Romanesque buildings were heavier in appearance than their Gothic counterparts. Inside, space was separated by thick walls into units. Gothic interiors, by contrast, were open. In eliminating interior walls, Gothic buildings created a sense of unified space. The sumptuous rows of shimmering stained-glass windows lining the walls of Gothic buildings contributed to the impression of uninterrupted space.

The wide spaces for windows afforded by Gothic architectural features contributed to a greater demand for stained glass windows. Artists would blow the glass into varying forms and sizes. Pieces were then cut into smaller fragments and assembled according to a design. Often, pieces were “painted” so details -- such as gestures and clothing -- could be represented. The challenges of creating stained glass masterpieces were only equaled by the difficulties workers experienced when they placed those intricate windows in their frames.

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Some of the most famous stained glass windows can be found in Chartres Cathedral, which was completed in 1220. Thanks to innovations in architecture, Chartres demonstrated the power that stained glass windows could wield more effectively than its predecessors. Most of the original stained glass is still intact in Chartres today; its colored light is part of what makes the cathedral a favorite tourist attraction. One of the most popular works of stained glass can be found in the famed Notre-Dame Cathedral (1345). There, an enormous stained glass window creates the impression of a rose of light that changes with the hours of the day, a seeming window to the heavens.

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Ultimately, the most important reason that stained glass windows remain a staple in churches even now is a matter of the Bible, not beauty. Stained glass was not merely attractive, it created an ethereal experience with a material object, glass, making the earthly into the divine. More important, stained glass was useful for a practical reason. In the medieval period, many church-goers were illiterate. The intricate scenes depicted in stained glass were not just decorations; they were ways of delivering religious messages to all viewers, even those who could not read the Bible for themselves. Stained glass embedded religious beliefs into the very walls.