In September 1827, Hector Berlioz attended a performance of Hamlet in Paris and became fixated on the Irish actress playing Ophelia, Harriet Smithson. He bombarded her with letters for three years and never received a reply. This episode examines how that unrequited obsession became the Symphonie Fantastique, a five-movement instrumental drama in which a despairing artist overdoses on opium and hallucinates his way from a ballroom to the guillotine to a witches' sabbath. We explore the idée fixe, the recurring melody named after a contemporary medical term for obsessive preoccupation, and how Berlioz mutated it across the work to chart his own deteriorating state of mind.

We break down the orchestral innovations that scandalized 1830 Paris: two harps in the ballroom waltz, four timpani players imitating distant thunder, strings struck with  ...