Ariel is a spirit who uses magic to help Prospero carry out his plans. Given Ariel’s evident power, it may seem odd that he would be willing to serve Prospero at all. So why does he do the magician’s bidding? The main reason is that Ariel owes what freedom he has to Prospero. Prior to Prospero’s arrival on the island, Ariel served Caliban’s mother, Sycorax. As Prospero reminds him in Act I, scene ii, Ariel fell out of favor with Sycorax, and she imprisoned him in a “cloven pine.” Ariel remained stuck in the tree for twelve years, during which time Sycorax died, abandoning Ariel to an eternity of pain. When Prospero arrived on the island, he found Ariel in torment: “Thy groans,” he explains, “Did make wolves howl and penetrate the breasts / Of ever angry bears” (I.ii.). Prospero freed Ariel from this prison, and he struck a deal in which Ariel would serve him faithfully for one year, after which he would be released from all service and return to freedom.