A special word should therefore be said about the dramatic treatment adopted. While the early opera derived its topic's and material from the ancient drama and its form from the mediaeval Mystery, it early settled into an arbitrary style of its own. The stories were at first wholly taken from Greek mythology, but tales from Roman, Jewish, Oriental or early Christian history were soon added, especially those that had already been used by Italian poets. The same subjects and the same plots constantly recurred with slight variations. Intrigues, entanglements through disguises and tricks, applications of magical or superhuman power, and the like, abounded. The denouement was always happy, however tragic the story, while absolute comedy became more and more frequent.
Personages were usually multiplied, both as actual participants and as a dumb spectacle. The a.ction was divided into three or more acts, each containing many scenes with shifts of setting, while at the beginning was usually a considerable prologue by mythological characters or personified ideas and at the end a licenza or epilogue of a dedicatory or apologetic nature.
Occasionally, poets of ability served as librettists (Busenello being named as the most gifted), but, as a rule, the texts were hack-work, often hasty, ill-conceived and bombastic, Especially where works were given as parts of lavish private festivities, but more or less in all cases, the expenditure for costumes, scenery and manifold accessories tended to be enormous. Great numbers of soldiers, slaves, citizens, etc., were introduced for spectacular effect, with quantities of animals, birds, plants and other natural objects. Huge or grotesque machines or figures were devised to heighten the illusions.