Mary, Mother of God
In 1969, the feast of Mary, Mother of God (formerly celebrated on October 11) was transferred to January 1.
The celebration of Mary as “Mother God” is the oldest of all Marian celebrations, going back at least to the third century.
The title is familiar because it is part of the Hail Mary (“Holy Mary, mother of God…..”). But in the early 400s great controversy surrounded it. Some argued that Mary was the Mother of Christ, but calling her Mother of God was going too far.
The other side argued that Jesus is truly God, and in bearing Jesus, Mary bore God
The Council of Ephesus in 431 resolved the matter, affirming that Mary is truly “Mother of God.” The documents of the council were in Greek, and the term used for Mary was “theotokos” which means “God-bearer.”