Prospero devoted all of his time to his study of the liberal arts. Prospero became renowned for his knowledge of the liberal arts but he neglected his duties as Duke of Milan.
Prospero gave his brother Antonio the power to run Milan so he could focus on his studies. Little did Prospero know that Antonio craved to be the sole Duke of Milan.
Antonio stole the power of the Dukedom from Prospero and turned his friends against him when Prospero wasn't paying attention. Antonio was able to take the dukedom with the help of the King of Naples.
Gonzalo heard of Antonios plan to banish Miranda and Prospero so he stocked their ship with supplies. Prospero was grateful for Gonzalos efforts.
Antonio banished Prospero and Miranda from Milan in the middle of the night. He hoped they would disappear and die at sea and never come back to Milan.
Prospero and Miranda by luck safely arrived at an abandoned island. Prospero felt betrayed by Antonio and the King of Naples and decided to plot his revenge. On the island, Prospero and Miranda met Ariel and Caliban who Prospero made into his servants.