After his international success with The Firebird in 1910, they and their family continuously moved around Switzerland and France until 1934, when they settled into their final home together along the Rue du Faubourg Saint-Honoré in the 8th arrondissement of Paris.

She was the principal copyist of his scores, counseled him on private and professional matters, and was an important influence in his reembrace of Eastern Orthodox Christianity.

In what musicologist Stephen Walsh called "an atrocious act of self-immolation", she acquiesced to Igor's demands to serve as an intermediary between him and Vera, establish an amicable relationship with her, and deliver the regular financial stipend he provided for her.

[8] Although Gavriil had purchased property in Ustilug at some point in the early 1880s for the sake of moving his wife to a location where the weather would not aggravate her tuberculosis, there is no record of the Nosenko family living there until 1889.

[9] A subsequent medical examination in June 1890 determined that Yekaterina had no trace of tuberculosis and that she was found to be "completely healthy", although in later life she became ill with the disease.

[12] The Nosenko estate was soon recognized as one of the finest in the Volhynian Governorate[11] and the family became known among locals for their charity work and efforts to improve social welfare.

In the late 1890s,[13] the Nosenkos built a free hospital, hired a doctor to attend to patients in the Ustilug area, and donated land for the establishment of a community cemetery.

[11] Later, when Yekaterina's sister married Grigory Belyankin, a graduate of the Marine Architecture Institute in Philadelphia,[14] the family built a school and fire station as well.

[17] The two encouraged each other's interest in painting and drawing, swam together often,[20] went on wild raspberry picks, helped build a tennis court,[22] played piano duet music,[23] and later organized group readings with their other cousins of books and political tracts from Fyodor Stravinsky's personal library.

[24] At the Ustilug estate they also mounted plays and entertainments, including Anton Chekhov's The Bear, which were acted by them and other members of the Nosenko and Stravinsky families.

Although as first cousins they were legally prohibited from marrying,[28] they were able to procure Father Afanasy Papov,[29] later described by the composer as "a kind of Graham Greene bootleg priest", to officiate the service without asking them for identification; Andrei and Vladimir Rimsky-Korsakov [ru] served as witnesses.

According to Igor's later reminiscences, he also began to develop in his mind the music for what later became the vocal cycle Faun and Shepherdess, a setting of erotic verses by Alexander Pushkin, which he dedicated to Yekaterina.

[31] After the honeymoon, the couple moved into the Stravinsky family home in Saint Petersburg along the Kryukov Canal, where they lived together with Igor's mother and brothers.

[39] During the summer of 1907, Igor designed and supervised the building of a new house for him and his family on the Nosenko estate in Ustilug,[40] which was built next to the residence of Yekaterina's sister and her husband.

[41] He called it a "haven for composition" and spent the summer months playing piano duet arrangements of Ludwig van Beethoven's symphonies with Yekaterina.

[38] Walsh speculates that the family's move was part of Igor's personal "grand plan" that had been spurred by the success of The Firebird and the "deep-seated Russian urge to escape from the icy grip of the northern winter".

She and her children returned to Ustilug, via Basel and Berlin; while Igor continued to Genoa[49] and Rome, where he completed his newest work, Petrushka.

[63] At some point during the second week of July, probably the 14th,[d] while in Paris after returning from London, Igor engaged in an adulterous affair with the wife of the painter Serge Sudeikin, Vera, whom he had first met in February.

By the end of July, Vera was sending Igor letters to his residence in Anglet, urging him to return to Paris, and pleading with him to give her errands to run on his behalf.

[68] According to Denise Strawinsky, the wife of Théodore:[69] For [Yekaterina] there now began the long and terrible agony of her life, and a veil of sadness was drawn forever over her beautiful face.

[72] What Yekaterina thought of the situation at this time is unknown for lack of epistolary evidence,[73] although Vera reported that she told her: "If there has to be another woman, I am glad that it is you".

[74] Igor supplied Vera with a regular stipend and an apartment in the Passy district of Paris, but delegated to Yekaterina with meeting his mistress at his bank and presenting her with the money, a task that Walsh described as "an atrocious act of self-immolation".

Her niece Tanya Stravinsky, who was then visiting, wrote to her parents in Leningrad on May 3:[77] They brought Aunt Katya in an ambulance ... Two days before she left [Rome], two liters of fluid were pumped out of her, as it was pushing intensely on her heart.

Vera visited and helped her with domestic tasks,[86] although she and Yekaterina "had never been friends in the real sense of the word, as has been improperly suggested", according to Denise Strawinsky.

[87] A quack, who had dubbed himself a "healer" and ingratiated himself among Russian Parisians, arrived in the Stravinskys' lives at this point; he claimed to be able to cure Yekaterina's tuberculosis by way of rhythmic breathing exercises that she had to take while scantily clad.

[109] Another niece, Xenia Stravinsky, recalled years later family impressions of Yekaterina in her youth:[98] This intelligent, profound, and exceptionally caring woman with her quiet charm.

In her youth and even later after she got married, Aunt Katya gave little consideration to her externals, dressed modestly...[98]Walsh, who wrote that Yekaterina's "beauty was not just spiritual", described documentary evidence of her appearance:[110] Photographs of her at the time of her marriage and before show a beguiling tenderness of facial expression: soft, deep-set eyes, a generous, but not sensuous mouth ... an air of calm inner poise ...

[110]Tanya, wrote to her parents during her stay with the Stravinskys in Nice that Yekaterina "looked very young", was "well dressed", and wore a discreet amount of makeup.

[81] In a letter dated March 17, 1935, she wrote to Igor:[113] You say that you look forward to a normal life, but you won't find one, and we will bear this cross that God has sent us, and we will not stop praising Him and thanking Him.

[99] Yekaterina was the only member of the family permitted into Igor's work room,[106] was the first to hear his new music,[117] of which she was an attentive listener,[118] and was the principal copyist of his scores.