In the centuries following the conquests of Alexander the Great the dramatic unification of the Mediterranean world created exceptionally fertile soil for the growth of new religions. Christianity, for example, was one of the innovative religious movements that arose during this time. However, Christianity had many competitors, and one of the most remarkable of these was the ancient Roman "mystery religion" of Mithraism.
Like the other "mystery cults" of antiquity, Mithraism kept its beliefs strictly secret, revealing them only to initiates. As a result, the cult's teachings were never...