Russian Wikipedia says this about "Запорожцы пишут письмо турецкому султану" ("Reply of the Zaporozhian Cossacks to Sultan Mehmed IV of the Ottoman Empire") painting by Ilya Repin:
После первого публичного обозрения художника критиковали за то, что по мнению многих картина была «исторически недостоверной».
After the first public viewing, the artist has been criticized because by many opinions, the painting was "historically inaccurate"
Moreover, it confirmed that assertion when discussing a second decade-later, smaller version of the painting that Repin started in 1889:
Второй вариант «Запорожцев» художник попытался сделать более «исторически достоверным»
the artist tried to make the second version of "The Cossacks" more "historically accurate"
Neither of the two statements in Wikipedia is referenced, in either Englisgh or Russian versions.
What specifically were the historical inaccuracies in this famous painting according to 1891 viewers?
Bonus question: Is the list of inaccuracies accurate in light of how we changed our historical knowledge in 2014?