en.wikipedia.org/wiki/Kyiv_Opera_House

The article identifies Mykola Lysenko's Christmas Night as "the first opera written in Ukrainian," but authoritative Ukrainian opera institutions attribute that distinction to Semen Hulak-Artemovsky's A Zaporozhian Beyond the Danube.

• The Odesa National Academic Opera and Ballet Theater states that Hulak-Artemovsky was the "author of the first Ukrainian opera" and says that A Zaporozhian Beyond the Danube was completed in 1862 and premiered a year later at the Mariinsky Theatre.
• The Dnipro National Academic Opera and Ballet Theatre states even more specifically that A Zaporozhian Beyond the Danube is "the first opera, the libretto of which was written in Ukrainian."

Because A Zaporozhian Beyond the Danube predates Lysenko's Christmas Night by about a decade, calling Christmas Night "the first opera written in Ukrainian" is incorrect.

The date in the article does not match authoritative histories of the theatre.

• The Encyclopedia of Modern Ukraine says the theatre began operations on 27 October 1867 with Verstovsky's Askold's Grave.
• The National Opera of Ukraine's own history page says 27 October old style / 8 November new style 1867 was the historic opening date when Kyiv Opera first raised the curtain.

Those sources support either 27 October 1867 (O.S.) or 8 November 1867 (N.S.). They do not support 6 November 1867.