79, is a lyric comedy, or opera, in three acts by Richard Strauss to a German libretto by Hugo von Hofmannsthal, their sixth and last operatic collaboration.

[1] The Western Hemisphere premiere was at the Teatro Colón in Buenos Aires on 16 August 1934, conducted by Fritz Busch, with Margarete Teschemacher in the title role.[2].

Meanwhile, Arabella is wooed by three suitors, Elemer, Dominik and Lamoral, and acknowledges that she may have to accept one of them, but has fallen in love at first sight with a stranger she passed in the street.

Arabella continues to muse about the strange man she noticed, but when Count Elemer arrives to be her escort for the evening, she tries to banish these thoughts and look forward to the excitement of the Fasching.

Mandryka tells her about his life and his country's customs, in which young women offer their fiancés a glass of water as a token of agreeing to be married.

Then Mandryka agrees to Arabella's request that she be allowed to stay for another hour to say farewell to her girlhood, during which she thanks her suitors for their interest in her and bids them goodbye.

Mandryka overhears this conversation and, mad with jealousy and disappointment (after first trying to evade these feelings), raises a commotion, flirting with the Fiakermilli, the ball's mascot.

After Mandryka accuses Arabella of infidelity and plans to go back to his land, Zdenka rushes in, no longer in disguise and in her negligee (making it clear that it was she who had the encounter with Matteo).

Arabella asks his servant to bring her a glass of water, and Mandryka thinks she has requested it for her refreshment.