A fragment of a score by Vincenzo Bellini (1801-1835) has been discovered at the Spanish National Library in Madrid. In fact it is a sketch for the duo ‘Tu m’apristi in cor ferita’ written for the opera ‘Il Pirata’ which was created at ‘Teatro alla Scala’ in Milan in October 1827. The music of this score does not correspond to the final version, which enhances the musicological value of the document on which one can read: ‘Manoscritto di Vincenzo Bellini e dei suoi fratelli Mario e Carmelo’.