Left: Canterbury Cathedral. Each scene illustrates an episode in the life of Christ.
Right: Strasbourg Cathedral. Four of the nineteen emperors depicted in the cathedral.
Most of the images of stained glasses of the middle age intended to help the illiterate public to learn about their faith. (remember there was no Gutenberg!)
The Strasbourg Cathedral shows it's political propaganda function and reveals the close connection of church and state.
The irony is that now those of us who are not aware of biblical facts have difficulty in understanding the biblical meaning of some stained-glasses or paintings. But we can enjoy their beauty.