The head of Ukraine’s Catholic Church announced on Monday a change to liturgical calendars this autumn that would see Christmas celebrated on December 25 rather than January 7, amid an effort by Ukrainian institutions to distance themselves from Russia.

Major Archbishop Sviatoslav Shevchuk, head of the Ukranian Catholic Church, announced that it will mostly stop using the Julian calendar, a liturgical calendar used almost exclusively by the Russian Orthodox Church and other eastern churches influenced by it.