When Alexander Grechaninov's opera Sister Beatrice on a text by Maurice Maeterlinck premiered in Moscow in 1912, it promised to bring together two conceptual worlds, those of symbolist aesthetics and the Russian Orthodox liturgy. Critics who hoped that Grechaninov's experience as a composer of sacred music would help bring alive the ‘unheard music’ of Maeterlinck's symbolist ‘Miracle Play’, however, were sorely disappointed. The opera drew scorn from critics for its overly concrete musical rhetoric, while conservative commentators levelled claims of blasphemy. In this article, I consider the two scenes depicting miracles in Sister Beatrice to demonstrate how it negotiated these competing perspectives, employing insights from religious philosophy as well as symbolist aesthetics. Drawing on new archival evidence, I also demonstrate how church and state censors co-participated with composers and critics debating whether and how the sacred might be displayed on stage and in sound.