At this day,26 February,1897,was born Irma ( Erich-Grimme) Duncan !

20-year-old Irma Duncan in a dance pose, 1917. Agence Rol, National Library of France.

Bibliothèque nationale de France, département Estampes et photographie, EI-13 (868)

Anna Duncan dancing on the beach ( Long Beach? ). Arnold Genthe, apr. 1917-1919. Library of Congress.

The Dance of The Future, New York, The Forest press, c. 1909. With introduction by Mary Fanton Roberts and samples of concert programs.

The Dance of the Future in Polish language. Izadora Duncan "Taniec przyszłości", WARSZAWA 1905. Polona library

Taniec przyszłości odczyt Izadory Duncan

Isadora Duncan's Concert Studio(ex-Isadora Duncan's Moscow School) perfomance for the school pupils,1935

After the closing down of the Isadora Duncan's Moscow School in 1929, it was reformed into "Isadora Duncan's Conert Studio".Their  artistic director was Maria Borisova, who replaced  Irma  after her leaving to USA.(Althought, according to the Isadora Duncan Archive, Tamara Lobanovskaya was their artistic director from 1930 to 1935. But the soviet press points at Maria.)
Their manager remained Illya Shneider, who was previously the headmaster of the Moscow school.
The footage starts with the title"Learnig the Ancient Greece Art", where it shows the school excurtion in  art museum. Later on, in this museum, the dancers of  Duncan Concert Studio shows the movement of the greek statues to the pioneers.

The famous Russian ballet dancer Michel Fokine shares his point of view about Isadora Duncan's art in his autobiography

Michel Fokine, 1936. Photo by Howard Coster.  © National Portrait Gallery, London

Michel Fokine saw Isadora Duncan's  perfomances for the first time  in  Saint-Petersburg, in 1904, during her Russian tour. Fokine was impressed by her, and,according to his colleges and Duncan researchers, was greatly influenced by  Isadora's ideas and dances, so it greatly affected on his choreography and his vision of ballet. He saw in Isadora the changes, that should be done in ballet, the thing that  he was thinking about for long time. But here what Fokine by himself thought about the barefoot dancer:
I wish to talk about Isadora Duncan in some detail. She was the greatest American gift to the art of dance. Duncan proved that all the primitive, plain, natural movements - a simple step, run, turn on both feet, small jump on one foot - are far better than all the richness of the ballet technique, if to this technique must be sacrificed grace, expressiveness, and beauty. It is true that one should not sacrifice beauty or grace to the execution of technical difficulties. The error is in the supposition that technical difficulties could not be executed with grace, as if beauty and expressiveness may be associated only with simple movements.

Isadora Duncan about her American tour of 1908 and Maud Allan, by C.C.Carlton. San Francisco Call, 8 November 1908