Who is Antonio?What crime did Antonio commit?

Antonio is the current duke of Milan and the treach erous brother of Prospero, the former duke of Milan. At the beginning of the play, Prospero tells Miranda how as duke he retreated to his studies after entrusting Antonio, "whom next thyself / Of all the world I lov'd," with the practical side of governing Milan (I.ii.66-78). Greedy for total power, Antonio usurped his brother with the help of King Alonso of Naples, and set Prospero and the infant Miranda adrift in a rotten boat. As the play opens, Antonio is traveling nearby on the ship carrying King Alonso and his courtiers home from Tunis—thus providing Prospero with the opportunity to bring his enemies to justice.