Two influential Christian theologians in particular had a profound impact on Western art: Tertullian and Augustine. Tertullian, in On Idolatry, argues that a true Christian cannot be an artist, for anything created by an artist has the power to be worshiped as an idol. The Ten Commandments explicitly denounces this, so any member of the clergy who also happened to like painting, according to Tertullian, needs to stop. They can instead become craftsmen, he says. Augustine denounced art in the name of Christianity because he thought that art was just a fancy way of lying. If an artist created a sculpture of a cat, that artist has created an illusion– what appears to be a cat to us is not in fact a cat. The artwork is attempting to convince its audience that it is real when it is simply simulacra, and Augustine takes the stance that this is no different than lying, which is a sin and should not be committed by true followers of God.
While the influence of these two men wasn’t great enough to convince Christians to stop making art altogether, they did alter the dominant style in a very noticeable way. Rather than abandoning their craft, Christian artists simply shifted their style away from Classical influences such as naturalism. They abandoned techniques that made their art appear realistic such as shading and perspective, and replaced them with flat, unrealistic representations of figures and scenes. This new style allowed artists to work uninterrupted by theologians fearing idolatry, though concerns, especially with the Byzantine iconoclasts, rulers who defaced art which they deemed too risky, still persisted.