Die Blaue Mazur (The Blue Mazurka) is an operetta by Franz Lehár.
Synopsis
The operetta takes place in Poland and deals with the initially unfortunate marriage of the Viennese Countess Blanka von Lossin with the Polish Count Olinski. Because of her husband's unfaithfulness, his wife leaves him and initially seeks her luck elsewhere. In the end, both spouses realize that they belong together.