Political, social, and artistic changes on a vast scale make the reign of Constantine the Great and, indeed, the entire fourth century the most confusing era in the history of Roman art. The fortuitous survival of the Arch of Constantine--with its historic relationship to the rise of Christianity as the state religion--has made this monument the focus of many questions about the emergence of the distinctly unclassical style that was eventually identified with the new religion. The Arch featured various classical sculptural elements taken from monuments of earlier reigns in addition to contemporary carving in the new style. Though there is little agreement among scholars as to the precise stylistic significance of the new style as represented on the Arch and the form in which it was eventually manifested as Christian art, it is clear that the Arch of Constantine stands at or near the divide between classical and Christian art.
The Arch was erected in celebration of Constantine's victory over his co-emperor Maxentius at the Milvian (or Mulvian) Bridge in 312. The Edict of Milan, granting freedom of worship in the empire and restoring various rights to Christians, was published in 313. Since the Milvian victory turned out to be an even greater triumph for Christianity than it was for the emperor the subsequent legend of the battle grew considerably. Constantine, it was claimed, had been led to victory by the sign of a miraculous cross that appeared in the sky during the battle. In Christian history this was seen as "a triumph of Christ and his viceregent Constantine" (Grabar 148). Because the battle formed such a distinct turning point in history the celebratory Arch, which was dedicated in 315, has long been seen as a primary piece of art historical evidence regarding the fourth century transition from classical to Christian art. It is true, of course, that in the civil wars that were concluded at the Milvian Bridge Roman s...