The years 1908 and 1909 were vital for establishing the reputation of Claude Debussy in Britain because of three significant events: Debussy’s visit to Britain to conduct Prélude à l’après-midi d’un faune and La mer at the Queen’s Hall in February 1908, the shambolic performance of Nocturnes in February 1909, and the long-awaited première of Pelléas et Mélisande in May and June 1909. British audiences and critics had already sought to find a language to describe Debussy’s ‘atmospheric’ orchestral music. This chapter gives insights into the advocacy work to prepare the British public for Pelléas, which was unlike any opera they had heard before. Focusing on the Symbolist writer, Arthur Symons, Debussy’s first biographer, Louisa Liebich, and influential critic, Edwin Evans, it considers how an understanding of Debussy in Britain was distinctive from that in France and influenced the wider reception and international standing of Debussy in the pre-war years.