The libretto is by Francesco Maria Piave . The story was based on a play SimÃ n Bocanegra ( 1843 ) by Antonio GarcÃ a GutiÃ rrez . Simon Boccanegra is an opera with a prologue and three acts by Giuseppe Verdi to an Italian libretto by Francesco Maria Piave , based on the play SimÃ n Bocanegra ( 1843 ) by Antonio GarcÃ a GutiÃ rrez .