In Narrative and Dramatic Sources of Shakespeare, Geoffrey Bullough observes that The Tempest's "didactic nature," as well as Prospero's "masterful aloofness" and "use of the supernatural" Though wary of such allegorizing, Bullough has "no doubt that in The Tempest, more than in the other 'romances,' Shakespeare was thinking of human life in a cosmic way," eliciting "a moral perfection in which reason and the affections would be united with grace." (1) Grace Tiffany notes that in the romances "grace" appears more often and with deepening meaning as Shakespeare moves "away from a dramaturgy emphasizing tragic choice to one focusing on divine rescue." (2) Divine activity is, however, complexly portrayed in The Tempest. Certainly Pericles, Cymbeline, and The Winter's Tale show central characters rescued from tyrants or their own tyranny, and innocents resurrected from death, by an intervening deity (Diana, Jupiter, Apollo) as well as by wise counsel or medical-magical ministry (Helicanus and Cerimon in Pericles; Belarius, Pisanio, and Cornelius in Cymbeline; Camillo and Paulina in The Winter's Tale) and by the talismanic power of a chaste maid (Marina, Innogen, Perdita). In The Tempest, however, "divine rescue" occurs with a difference. Unlike previous protagonists (Pericles, Posthumus, Leontes) who steadily decline in moral agency, Prospero is a benevolent magus who uses supernatural power (or a theatrical simulacrum thereof) to redeem an entire ship of state. Though he too has engaged in a neglectful quest, received aid from a wise counselor, and been inspired by an angelic daughter, he now shows virtuoso control of "spirits" who can alter both settings and to some degree souls by means of magical/theatrical productions.