When he speaks to Ariel, a magical creature over whom his mastery is less certain than over his doting daughter, Prospero goes to even greater lengths to justify himself. He treats Ariel as a combination of a pet, whom he can praise and blame as he chooses, and a pupil, demanding that the spirit recite answers to questions about the past that Prospero has taught him. Though Ariel must know the story well, Prospero says that he must “once in a month” recount Ariel’s history with Sycorax, simply to ensure that his servant’s fickle nature does not cause him to become disloyal. Every time he retells Ariel’s history, we feel, he must increase both the persuasiveness of his own story and his control over Ariel. This is why he now chooses to claim that Ariel is behaving badly—so that he can justify a retelling of the history, even though Ariel is perfectly respectful. He forces Ariel to recall the misery he suffered while trapped in the pine tree (“thy groans / Did make wolves howl,” I.ii.289–290). He then positions himself as the good savior who overthrew Sycorax’s evil. However, he immediately follows this with a forceful display of his own magical power, threatening to trap Ariel in an oak just as the “evil” Sycorax had trapped him in a pine. In this way, Prospero exercises control both intellectually and physically. By controlling the way Ariel and Miranda think about their lives, he makes it difficult for them to imagine that challenging his authority would be a good thing to do, and by threatening Ariel (and, shortly thereafter, Caliban) with magical torture, he sets very high stakes for any such rebellion. For his part, Ariel promises to “do my spiriting gently” from now on.