The „Csárdásfürstin"
Kálmán continue to work on the „Csárdásfürstin" only in 1915. In June, the composer went to Bad Ischl, where several well-known composers spent regularly the summer months. Kálmán rented the „Rosenvilla", a house with great musical tradition: Giacomo Meyerbeer composed here parts of his „Prophet", later it accommodated for a while Johannes Brahms, the violinist Joseph Joachim and finally Franz Lehár. Before Kálmán could finish the instrumentation of „Csárdásfürstin", he heard about the death of his brother Béla.
He had to interrupt the work again, although the première of his new work was already set. After turbulent rehearsals, it was performed for the first time on November 17th 1915 at the Johann-Strauss-Theater and scored an unprecedented success. It was the only work kept on the program of the Johann-Strauss-Theater during the whole year. Soon, the operetta was abroad as popular as in Vienna. Later, two films were made of it.
The libretto of the famous authors Béla Jenbach and Leo Stein treats a classical theme of the operetta: The misalliance of a young aristocrat with a chanteuse. Each number of the work shows ripe mastery in inventing popular hits: From the march melodies „Die Mädis vom Chantant" or „Jaj, mamám, Bruderherz, ich kauf' mir die Welt" and the waltz themes „Tanzen möcht' ich, jauchzen möcht' ich", „Machen wir's den Schwalben nach" or „Tausend kleine Engel singen: Hab mich lieb" to the great ensemble scenes.
For the next operetta, Kálmán engaged Alfred Maria Willner and Rudolf Österreicher (later Kálmán's biographer) as librettists. They were to transform „Fräulein Susi", which met little success, into „Die Faschingsfee". The initial position of the „Csárdásfürstin" is reversed here: A princess falls in love with a painter in Munich at the time of the artists' festivities in Schwabing. It has also a happy ending. At first, the première on September 21st 1917 at the Johann-Strauss-Theater achieved only a lukewarm success, but then the rousing musical acts won through slowly: The waltzes „Küß mich, holde Faschingsfee" and „Liebe, ich sehn' mich nach dir" and particularly the song „Lieber Himmelvater, sei nicht bös".

THE CSÁRDÁS PRINCESS

Prelude
November 1915 - Fourth Battle of the Isonzo
The world is in shambles. The Austro-Hungarian Empire is dying in World War I.

Act I
The Spring of 1914 - The "Orpheum" Cabaret in Budapest
Celebrated singer Sylva Varescu is giving her farewell performance in Budapest before leaving for a tour of the United States. Edwin Lippert-Weylersheim, a young nobleman from Vienna, specially regrets to see her go: he has fallen in love with her. Just like his friends, Count Boni and Feri-Bácsi, he spends most of his time at the cabaret theatre. Edwin's parents are very much against this, they send Eugen Rohnsdorff, a relative, to hand him his draft order. Edwin does not know that back in Vienna they have already announced his engagement to his cousin Countess Stasi.

Edwin wants to keep Sylva from leaving for America, and as he has received his orders for military exercises, he does not see any other chance to hold her back than promising to marry her by signing a notarial deed to that effect. He commits himself to marrying Sylva within twelve weeks' time. An impromptu wedding celebration takes place after Sylva's farewell performance at the "Orpheum".

INTERMISSION

Act II
June 1914 - The Lippert-Weylersheim Palace in Vienna
At a party, the Prince and Princess Lippert von Weylersheim plan to announce to the high society of Vienna that their son Edwin is engaged to his cousin Countess Stasi. Sylva appears in the company of Boni, claiming to be his wife. Edwin is still in love with Sylva, asking Boni to divorce her, specially because the latter falls in love with Stasi the moment he sees her. Again, Sylva believes in what Edwin says and agrees but when she finds out that she will only be accepted by society as the purported Countess Kancsianu, she is deeply disappointed and reveals her true identity to the party. A perfect scandal.

Act III
A first-class hotel in Vienna.
The protagonists are reunited at the hotel. Boni tries to console Sylva. However, the only one who can cheer her up is Feri-Bácsi, who accompanied the Orpheum showgirls on a tour. Edwin rushes in to confess his unconditional love to Sylva but he cannot find her. At the same time, the Prince tries to prevent his son's mésalliance. Feri-Bácsi recognises Edwin's mother, the Princess: he once was in love with her when Hilda was still the primadonna of a theatre in the province. In view of this, Prince Lippert von Weylersheim gives in to Edwin and agrees to the marriage with Sylva. Stasi and Boni receive his blessing, too.
Everybody - with the exception of the Prince and the officers - will join Sylva on her next American tour. A few days later, World War I is to break out.