Through a critical examination of various musical and gestural-related aspects of Rossini's celebrated Il Barbiere di Siviglia, I have tried to read its most famous number – Una voce poco fa – in the context of current musicological scholarship. This interpretation deciphers the components of the Code of Rosina's sophisticated characterization, and also reveals some new aspects of the structure, dramaturgy and compositional concept of the piece. In fact, Rosina is found to be the engine of the entire opera, a new type of femininity, which accords with the Goethean principle of the Eternal Feminine. A correlation noted between the evolution of the performance practice of Una voce and the musicological discourse, which occurred in the last fifty years, could promote further research on Rossini in particular and Italian opera in general.