The Prince and the Pauper — Mark Twain

They are the same age. They look alike. In fact, there is but one difference between them: Tom Canty is a child of the London slums; Edward Tudor is heir to the throne of England. A chance encounter leads to an exchange of clothes--and roles with the pauper caught up in the pomp and folly of the royal court, and the prince wandering horror-stricken through the lower depths of sixteenth-century English society.