Analysis of information sources in references of the Wikipedia article "Дванадцять днів Різдва" in Ukrainian language version.
January 5th: Twelfth Night or Epiphany Eve. Twelfth Night, the last evening of the traditional Twelve Days of Christmas, has been observed with festive celebration ever since the Middle Ages.
The Twelve Days of Christmas ... in most of the Western Church are the twelve days from Christmas until the beginning of Epiphany (January 6th; the 12 days count from December 25th until January 5th). In some traditions, the first day of Christmas begins on the evening of December 25th with the following day considered the First Day of Christmas (December 26th). In these traditions, the twelve days begin December 26[th] and include Epiphany on January 6[th].
On the Twelve Days of Christmas Alleluia. Unto us a child is born: O come, let us adore Him. Alleluia.
The Twelve Days of Christmas ... in most of the Western Church are the twelve days from Christmas until the beginning of Epiphany (January 6th; the 12 days count from December 25th until January 5th). In some traditions, the first day of Christmas begins on the evening of December 25th with the following day considered the First Day of Christmas (December 26th). In these traditions, the twelve days begin December 26[th] and include Epiphany on January 6[th].
On the Twelve Days of Christmas Alleluia. Unto us a child is born: O come, let us adore Him. Alleluia.