Every Inch a King
Harry Turtledove
 The book centers around Otto of Schlepsig, a circus performer and tightrope walker, who is surprised to learn that he's an almost dead-ringer for Prince Halim Eddin, recently invited to become king the newly independent country of Shqiperi. Fed up with his life in the circus, Otto, and his friend, the sword swallower Max of Witte, get some uniforms and set out to take the Prince's place as King of Shqiperi.