Virtue rampant. It’s something of a drawback when an opera has no characters, but this wasn’t always so. At the height of the 18th century’s classical style, an emblem would suffice, or a slightly animated statue. In Mozart’s Idomeneo something like the ideal is achieved. No one is really flesh and blood but rather personified virtues: Nobility caught between Filial Devotion and conflicted love from Chaste Constancy and Heartfelt Passion. Or as the playbill has it, Idomeneo, king of Crete, is trapped by a vow to Poseidon to sacrifice his son, Idamante, while two women pine longingly, Ilia, a captured princess of Troy, and the infamous Electra, daughter of Agamemnon. These pawns on the Greek chessboard were available to any dramatist or poet of Mozart’s day, to be shuffled through the paces of opera seria, the musical equivalent of high tragedy.