It Was a Gay Ballnight(1939)

1865. Katharina goes to a ball in Moscow. There she meets again Tchaikowsky, her first and only love. The young, who is now married to wealthy Michael Iwanowitsch Murakin, a man she does not love, has not forgotten Piotr Illich, the (not yet) famous composer. Both are still in love with each other but Piotr is engaged to Nastassia, a dancer, while for her part Katharina cannot leave her husband. Tchaikowky's first love then decides to sacrifice her happiness to the success of the composer, sponsoring him in secret. Something Piotr will learn only years after. When Katharina finds herself free at last it is too late: Tchaikowsky is dying of cholera and she only has time to close his eyes.