The Solemnity of Mary, Mother of God also known as the Solemnity of the Holy Mother of God is a Christian feast celebrated on January 1 on the Roman Catholic liturgical calendar. In the old Latin calendar, the feast was known as Circumcision of the Lord. The first of January is the octave day of Christmas and thus an extension of the Feast of the Nativity of Our Lord. In many countries this day is a holy day of obligation. According to the New Testament, Mary (Judeo-Aramaic מרים Maryām Bitter; Arabic مريم (Maryam); Septuagint Greek Μαριαμ, Mariam, Μαρια, Maria; Geez: ማሪያም, Māryām; Syriac: Mart, Maryam, Madonna), was the mother of Jesus of Nazareth, who at the time of his conception was the betrothed wife of Saint Joseph (cf. ... Russian Orthodox Icon of the Theotokos Theotokos is a Greek word that means God-bearer or Mother of God. It is a title assigned by the early Christian Church to Mary, the mother of Jesus, at the Third Ecumenical Council held at Ephesus in 431. ... Circumcision cuts some or all of the foreskin (prepuce) from the penis. ... Christmas or Christmas Day is an annual holiday that marks the traditional birthdate of Jesus of Nazareth. ... In the Roman Catholic Church, the Holy Days of Obligation are the days, other than Sundays, on which the faithful are required to attend Mass. ...

The feast is a celebration of the motherhood of Mary both divine and virginal. The title, “Mother of God,” is a western derivation from the Greek, “theotokos,” literally translated God-bearer. The term “theotokos” was adopted at the ecumenical council at Ephesus as a way to assert the divinity of Christ, from which it follows that what is predicated of Christ is predicated of God. So, if Mary is the mother of Jesus, she is the mother of God. Therefore, the title, “Mother of God”, and the “Solemnity of Mary, Mother of God”, which celebrates her under this title, are at once Mariological and Christological. As the conclusion of the octave of Christmas, this feast demonstrates for Catholics that Mary’s role is always to direct the believer toward her son. In Christianity, an Ecumenical Council or general council is a meeting of the bishops of the whole church convened to discuss and settle matters of Church doctrine and practice. ... Historical Map of Ephesus, from Meyers Konversationslexikon 1888 Ephesus (Greek: , Turkish: ), was one of the great cities of the Ionian Greeks in Anatolia, located in Lydia where the Cayster River (Küçük Menderes) flows into the Aegean Sea (in modern day Turkey). ... Jesus (8–2 BC/BCE to 29–36 AD/CE),[1] also known as Jesus of Nazareth, is the central figure of Christianity. ...