Literally, “God-bearing,” this title of the Mother of God was given to the Blessed Mother in the fourth century and signified the widespread devotion to the Blessed Virgin Mary.
The term was used as part of the popular piety of the early first millennium church, and which continues to the present day in both the Eastern and Western Churches.
The term was disputed in the early fifth century when the Nestorian heresy denied the divine maternity of the Blessed Virgin.
The doctrine of the Blessed Virgin as the Mother of God was confirmed by the third ecumenical council of Ephesus in 431 to preserve the teaching of the Church that Jesus was both Divine and human, and that the two natures were united in His One Person. (7:41)