Gregorio Allegri’s output covered almost every musical genre of his time: strict polyphony to monody, instrumental music and the cantata. He is now remembered principally for the nine-voice Miserere (1638), made famous in the 19th c. version requiring a high C in the coro favorito. Five years of bibliographic and musical research in Italy and abroad have permitted rediscovery of his well-rounded personality, and, from this point of view, the Tactus world premier recording of pieces contained in the Altemps manuscripts undoubtedly adds an important new chapter to the history of sacred music.