Bohemia was a historical country, later becoming part of the Czech Republic.
In the fictional world of Sherlock Holmes, the Bohemian king had a mistress, with whom he had ended the relationship. In London, an emissary of the king claimed that he was accosted by gypsies, who happened to have stolen a photograph, to the police. Inspector Lestrade brought the man to Sherlock Holmes' residence at 221B Baker Street. Holmes deduced that this emissary of the king still had the photograph, by taking it from the man's jacket. Furthermore, he deduced that the emissary was actually working against the king, hoping to blackmail him with this photograph, which was of the king with his ex-mistress. (TNG: "Elementary, Dear Data")