Mark Twain 
The Prince and the Pauper 

The story of two young boys who are identical in appearance: Tom Canty, a pauper who lives with his abusive father in Offal Court off Pudding Lane in London, and Prince Edward, son of King Henry VIII. One day Tom is nearly caught and beaten by the Royal Guards; however, Edward stops them and invites Tom into his palace chamber. There the two boys get to know one another, fascinated by each other’s life and their uncanny resemblance. They decide to switch clothes temporarily.