In 1918, in the Soviet Union, January 31 under the Julian Calendar system was the last day of its use.

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Before the Revolution, Russia had not yet adopted the Gregorian calendar, introduced by Pope Gregory XIII in 1582 to mitigate the errors of the Julian calendar, which owes its name to the Roman emperor who had chosen it 46 years before the birth of Jesus Christ.

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Typical Belarusian New Year celebrations take place according to the 'old' Julian style calendar and are combined with distinctive local performing arts.

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On the contrary, no feast day for Sol is mentioned on that day until 80 years later in the Calendar of 354 and, subsequently, in 362 by Julian the Apostate in his Oration to King Helios (the Sun).

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