There are many publications on the Internet that the caretakers had to prevent Repin in every possible way if he wanted to visit the Tretyakov Gallery and tries to rewrite his paintings. Let's figure out if this was really.
Apparently, the legend comes from the book of memoirs of Nikolai Mudrogel. He began to work with Tretyakov as a young man and even lived in the house of the collector, where he watched his work and environment. The Mudrogel gave the gallery almost 60 years of his life and left memoirs, in which he reflected on art, talked about Tretyakov and his relationship with Russian artists of that time, including Repin.

The Mudrogel recalls that Tretyakov simultaneously appreciated and was afraid of Repin, who "did not cost anything instead of correcting some small place in the picture, to rewrite much more." At the same time, not everyone liked the updated canvases, and it was precisely because of this that the conflict with the owner of the gallery occurred.
In 1885, Tretyakov bought the picture "They did not wait." The newspapers wrote that the face of the people who returned from the exile "does not in harmony with the faces of the family." Two years later, when Tretyakov was not in Moscow, Repin came to the gallery and assured the keepers, supposedly he was allowed to correct the canvas. After half an hour of work, the artist, already not asking anything about anything, moved to “Ivan the Terrible and his son Ivan” and changed the tone of the king’s face, and then headed for the “godfather in the Kursk province” and made a more “dusty” background. Without waiting for Tretyakov’s return, Repin went back to Petersburg, from where he sent the collector letter:
You already, of course, know that yesterday I was in your gallery; I tucked what was needed, in the film “Ivan the Terrible”, finally corrected the face of the “did not wait” in the picture (now, now, I think so) and touched a little dust in the “godmother”-was red.
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Yes, regarding your gallery: the 1st large hall has now become very ugly: many things monotonous in tone and size are full of size; The big paintings are not given the right places. The impression is restless and invisible.
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In general, the placement was very upset, only mine hang well.