Allegri's Miserere, with it's heartbreaking harmonies, it's verses alternately chanted and ornamented, it's seraphic voices, is sheer Baroque magic. Since it's composition in Rome in 1630, the work has constantly been transformed. Le Poème Harmonique approaches the score through the prism of it's metamorphoses, the ornaments and transpositions added since the time when Mozart himself transcribed the piece, then jealously guarded by the Vatican, which punished publication of it with anathema. From the Renaissance onwards, musicians dressed up the finest secular tunes of their time in sacred words. The most famous example of all, the Pianto della Madonna, in which Monteverdi transferred to the Virgin Mary the mournful strains of his Lamento d'Arianna, illustrates these exchanges between repertories. Similarly, his famous Sì dolce è 'l tormento is here transformed into Sì dolce è 'l martire with the help of the mysterious Virgilio Albanese. Other masters of the period, such as Rossi, Mazzocchi and Marazzoli, also adapted their works to sacred texts. With this programme, which builds on the experience of the album Nova Metamorfosi, one of Le Poème Harmonique's major triumphs, Vincent Dumestre celebrates the twentieth anniversary of his ensemble.