Caption:
"Shapur, King of Persia, Humiliates the Roman Emperor Valerian," an illustration from c.1413-1415 that appears in a book by Boccaccio. Shapur I, king of Persia, mounts his horse by standing on the back of the Roman emperor Valerian. After a series of wars against the Romans, Shapur defeated Valerian at Edessa in A.D. 260 and kept him captive for the rest of his life.