A mashup of Gluck’s mythological heroics with sitcom fluff for the tired businessman, Ariadne auf Naxos unfolds in the private theater of the fattest of fat cats in Vienna, a booby we never get to see. The piece is a gem, yet in its original form it pleased very few. In that version, the evening got off to a slow start with Molière’s entire play Le bourgeois gentilhomme, devoid of music but for delicious instrumentals for relief (they survive today as a concert suite). The definitive Ariadne scraps Molière in favor of a (mostly) sung prologue dominated by a volatile young composer inspired by Mozart. Connoisseurs adore him, and rightly so. —M.G.