On 9 May 1911, the Vatican placed on the Index of Prohibited Books all of the love stories and dramatic works of Gabriele d’Annunzio, but not his poetry.
What led the Vatican to take this step was d’Annunzio’s collaboration with Claude Debussy on the musical play Le martyre de Saint Sébastien [The Martyrdom of St Sebastian]. The Jewish actress Ida Rubinstein had been cast to play the role of Saint Sebastian, indeed d’Annunzio had written the part of Saint Sebastian specifically for her. But the fact that the Christian saint would be played by a Jewish women outraged French Catholics. Moreover, d’Annunzio’s play identified Saint Sebastian with the pagan figure of Adonis and neither d’Annunzio nor Debussy were Catholic. Needless to say, neither the Vatican nor Parisian Archbishop, Cardinal Leon Adolphe Amette, expected the play to present an account of Saint Sebastian which would promote Catholic faith and spirituality.
While there was some question as to whether the Vatican prohibition would, in fact, encourage more people to see the performance; the Vatican believed that it would be giving greater moral authority to the Archbishop in regards to his response to the play. Indeed shortly before the opening night of the production, the Archbishop issued a statement reminding Parisian Catholics about the Vatican’s prohibition and that they should not attend any play which “offended Christian consciences”.
The play was not successful, though it is not known whether that was because of or in spite of the actions of the Vatican and Cardinal Amette.
New York Times article about the Vatican and Amette response to d’Annunzio’s play