At the Metropolitan Opera, they revived Les Troyens, in the 2003 production by Francesca Zambello. Les Troyens is Berlioz’s magnum opus. Some regard it as a masterpiece of masterpieces, a peak of art. Others find it a bit of a snoozeroo. I remember something Ben Heppner, the tenor, said about another French opera, Debussy’s Pelléas et Mélisande: “four hours of French Novocain.” Les Troyens is longer. It is also a masterpiece, just as its admirers say. It needs a conductor, however, to bring out its greatness. It won’t quite play itself. The conductor must have a heightened sense of pacing, nuance, beauty, and so on. He must understand gentle grandeur. There are many singers in this opera, but it all rides on the man in the pit, I believe.

On this...