Liturgy
Solemnity of Mary, the Holy Mother of God
Solemnity · January 1 · Christmas season
The oldest Marian feast of the Roman liturgy, celebrating Mary's divine motherhood (Theotokos) on the Octave Day of Christmas.
Celebrated on January 1, the Octave Day of Christmas, this solemnity honors Mary under the title Mother of God, defined at the Council of Ephesus in 431. It is also the World Day of Peace and a holy day of obligation in many places.