Sassanid CameoIn this cameo — a type of jewelry made by carving into a multicolored piece of rock — the Sassanid king Shapur and the Byzantine emperor Valerian fight on horseback, each identifiable by his distinctive clothing and headgear. This does not record an actual hand-to-hand battle, but uses the well-muscled rulers as symbols of their empires. (Erich Lessing/Art Resource, NY)