It all started with voices – voices not meant to be heard. Verdi's demand that at crucial moments in Macbeth the performers stifle vocal expression is by now famous. Again and again he urged that the duet and sleepwalking scene be sung ‘sotto voce’, ‘with mutes’, that the singers should speak more than sing, that their voices should sound ‘harsh’, ‘stifled’, ‘hollow’, ‘veiled’. Verdi's wilful insistence that his singers not sing has been understood as part of the composer's struggle to curb the excesses of primo ottocento opera and invest it with a new psychological depth. Gilles de Van, for example, argues that the suppression of the voice in Macbeth creates a shadowy subjective interiority, and claims further that the decision represents a shift in Verdi's aesthetic orientation from ‘melodrama to music drama’. De Van understands Verdi's inward turn as a renunciation of the kind of extroverted display upon which melodrama relies, as a ‘turning point, the beginnings of a dramaturgy of interiority that does away with the superb transparency of traditional melodrama and marks Verdi’s new awareness of the aura of confusion and ambiguity that can inhabit the human soul'.