One central issue in the history of religious symbols within Christianity has been the Biblical prohibition against idolatry. While, on the one hand, religious symbols, art, and iconography can serve as an aid to faith, they can also become idols, worshiped in place of the things that they represent. Although the more important theological works on this topic actual originate from the iconoclast controversies in Orthodox Christianity, some of the same issues occur in Roman Catholicism.
The main theory justifying use of religious art is one that actually originated in Plotinus and other neoplatonic philosophers of late antiquity, who argued that beautiful works of art lead the viewer not to look simply at the sensual beauty of the portraits and the objects being portrayed but rather led the soul of the viewer to direct apprehension of the forms in a manner called "anagogy". When transferred to religious contexts, this means that a viewer looking at religious art, for example a painting of Christ or a crucifix, is drawn past the external image to contemplation of divine truth.
Many forms of popular worship involve representations such as statues of saints. While the Roman Catholic Church hierarchy approves of church art, including relics and images of saints, at times the Church tries to restrain or regiment popular cults when those seem to spill over into the realm of idolatry or the worship of the images or saints themselves, as a opposed to use of saints and images thereof as a path towards worship of God.