 ("Euridice" had received its first performance in October 1600).The music historian Joachim Steinheuer comments that Cavalieri was a pioneer of "recitation in singing or 'recitar cantando' "; this type of declamation was a major innovation in enabling the introduction of extended dramatic monologues and dialogues, as required in opera.Since the "Rappresentatione" is fully staged, in three acts with a spoken prologue, it can be considered to be the earliest surviving opera.