A spectre haunted the first weekend of the City of Birmingham Symphony Orchestra’s Debussy Festival: the spectre of Richard Wagner. Debussy’s relationship with Wagner began with infatuation, and ended (as so often) in open rebellion. The young decadent who declared Parsifal ‘one of the loveliest monuments of sound ever raised to the serene glory of music’ later ranted that ‘30 million Boches cannot destroy French thought’ even while, tormented by cancer, he laboured to complete three late sonatas of near-infinite subtlety and grace.