Answer:
From these lines, we learn that Prospero was the Duke of Milan who was dethroned from his dukedom while Miranda was his only heir and a supposed princess.
Below is an excerpt from the lines as an evidence:
PROSPERO:
Twelve year since, Miranda, twelve year since,
Thy father was the Duke of Milan and
A prince of power.
MIRANDA:
Sir, are not you my father?
PROSPERO:
Thy mother was a piece of virtue, and
She said thou wast my daughter; and thy father
Was Duke of Milan; and thou his only heir
And princess no worse issued.
Step-by-step explanation:
This is culled from "The Tempest" play by William Shakespeare. In the story, Shakespeare reveals an exiled ruler that made use of magic to restore his daughter . It also gives information on the consequences of the European settlement in the New World.