The following is a 19th century stained glass window from the Church of St. Peter in Nottingham, United Kingdom:

Source: Art in the Christian Tradition , a project of the Vanderbilt University Divinity Library, Nashville, TN. Original source: Flickr

Stained glass is not just highly decorative, it’s a medium which has been used to express important religious messages for centuries. Literacy was not widespread in the medieval and Renaissance periods and the Church used stained glass and other artworks to teach the central beliefs of Christianity. In Gothic churches, the windows were filled with extensive narrative scenes in stained glass — like huge and colorful picture storybooks — in which worshipers could ‘read’ the stories of Christ and the saints and learn what was required for their religious salvation. (Source: Victoria and Albert Museum )