Art: The Wittelsbach Treasure

To the roly-poly ruler of Renaissance Bavaria, diamonds were a duke's best friend. Albrecht V nearly emptied the privy purse in 1565 to buy the 27 jewel-studded pieces—primarily cups and goblets—that formed the original Schatzkammer (treasure chamber) of the Wittelsbach family, which ruled Bavaria from 1180 to 1918. But to Albrecht, competing for glory with monarchs from Madrid to Moscow, it was worth every pfennig. Over the centuries, the treasure grew in splendor and size; its 1,224 pieces rank it with the four largest royal treasure chambers that survived the decline of...