What is Christian Iconography?
"The science of the description, history, and interpretation of the traditional representations of God, the saints and other sacred subjects in art.
Almost from the beginning the Church has employed the arts as potent means of instruction and edification. In the first centuries the walls of the catacombs were decorated with paintings and mosaics, and in all later times churches have lent their walls, ceilings, and windows as well as their altars, furniture, and liturgical vessels and books, to be adorned with scenes from the Old and the New Testament, from the lives and legends of the saints, and even from old mythologies, modified, of course, and harmonized with Christian teaching."
~ The Catholic Encyclopedia