The Ara Pacis Augustae, or Altar of Augustan Peace, was built to commemorate the return to Rome of the emperor Augustus and his general Agrippa, who had been away for many years on military campaigns. Dedicated in 9 B.C., the monument consists of an altar and surrounding wall, both decorated with a series of processional friezes. Art historians and archaeologists have made the Ara Pacis one of the best-known, most-studied monuments of Augustan Rome,...