The events that take place in the play are all made possible by the original usurpation against Prospero, the right Duke of Milan by Antonio, his brother, the usurping Duke of Milan. The usurpation itself is made possible initially because Prospero has become increasingly more spellbound by his library of books, the same books which he later uses to exact his revenge. This is to say that not only are these books primarily the sole cause of Prospero's loss of power, but they are also entirely responsible for Prospero's dukedom being reinstated, because the magic they grant him gave him the power to do just that. This is one example of how power will always end up back in its rightful place.
In regards to the usurpation, Antonio (in league with Alonso) decides to overthrow Prospero's dukedom. In exchange for Antonio's homage and tribute, the king levied an army, removed Prospero from his rightful position as duke and replaced him with Antonio, the new Duke of Milan. The play's view of the natural order was based on the hierarchy of all beings and things. According to this view, when the hierarchy was destroyed, disorder and chaos reigned. All would go well as long as individuals in families and the larger society knew their place. Antonio's selfish refusal to recognize his particular place in the social and political hierarchy resulted in the overthrow of Prospero's dukedom and the consequent corruption of the "natural" harmony. Prospero expresses his disdain for Antonio and his will to regain power when he says:
I pray thee, mark me, -that a brother should
Be so perfidious! he whom, next thyself,
Of all the world I loved, and to him put
The manage of my state; (5)
So dry he was for sway, wi' the King of Naples
To give him annual tribute, do him homage,
Subject his coronet to his crown, and bend
The dukedom, yet unbow'd, -alas poor Milan!
To most ignoble stooping. (6)
The first essential step that Prospero takes in order to regain his dukedom is to construct the storm (or tempest) itself. This storm, which rocks with force the very ship that Prospero's enemies are on, overturns the hierarchy on the ship. The storm at sea is instilled by Prospero's magic which permeates the actions of the characters until Act V when he removes his magician's robe. Not until then has its purpose of restoring his dukedom been accomplished. In a social and political society, the king would almost always exercise his authority over all of his subjects, but on this ship at sea he has stepped into the domain of the Ship-master and Boatswain and must now give in to their authority. These are the people who hold the king's life in their hands. The Boatswain sums it up nicely in saying, "What cares these roarers for the / name of king?" (1). The king is not more powerful than the roaring sea. The aristocrats attempt to control the situation but only end up making things more difficult for the mariners, since they have no idea what they are talking about. Alonso and Antonio insist upon asking for the Ship-master repeatedly, and the Boatswain expresses their futility when he says, "Do you not hear him? You mar our labour: keep your cabins: / you do assist the storm" (1). This reversal of hierarchy foreshadows the major reconstruction of hierarchy that will take place by Prospero's hand throughout the rest...