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In Eastern Christianity, Annunciation of the Theotokos, which is when the archangel Gabriel told the Virgin Mary that she will become the mother of Jesus Christ the Son of God, is celebrated by the Greek Orthodox Church on this day.
Because Mary - the "Theotokos" or "Mother of God" - freely accepted this responsibility, this day is considered to be a day of joy and spiritual liberation.
Here are some ways you can observe this day according to Eastern Christian tradition: