Making stained-glass windows is an expensive business, today as it was in the past. The materials, specialist craftsmanship, artistic expertise and time it takes are all costly. It was the bishop who took the decision to build a cathedral and the main decisions on how it would be funded. The bishop of Chartres, Reginald of Bar, was an aristocrat close to the royal family. First cousin to king Philip II of France, he was an ambitious man who welcomed the rebuilding of the cathedral, seeing it an opportunity to increase his prestige. He was surrounded by the chapter of canons, clerics responsible for carrying out the liturgy of the cathedral, who at Chartres numbered some seventy-two. They jointly invested their wealth, acquired from their vineyards and cereal crops grown on the Beauce Plain, in this imposing project.

These men were also scholars. As a result of their study of the Scriptures, reading the writings of the fathers of the Church, attending daily liturgical readings and extensive travel, these were very learned men who as a result constructed an extremely complex iconographic programme. Chartres was a very active centre of pilgrimage. The images in the stained-glass windows were for the consumption of these crowds of pilgrims as well as local Christians, who gazed at these the bright images of their faith in the walls of the building and also donated money to help fund the work.