Marian devotees know January 1 is not just a day that starts the brand-new year, but a day when we contemplate the role of Mary in the life of Jesus Christ.
Called the Solemnity of Mary, Mother of God, this holy day of obligation calls upon every Catholic to attend Mass and refrain from working or engaging in activities that prevent them from worshiping the Lord. It is also called the Octave Day of Christmas because it falls eight days after December 25. (Read: Pope Francis Proclaims 2021 as Special Year of St. Joseph)
Learn more about the Solemnity of Mary, Mother of God with these three interesting facts about the day dedicated to our beloved Mama Mary!
The Solemnity of Mary, Mother of God Is Not Solemn

Solemnities, as defined by a catholic website, are “celebrations of the greatest importance,” higher in rank than feasts and memorials. The faithful begin observing solemnities on the eve of its date and recite the Gloria and the Creed. Some solemnities even have their own Vigil Mass.
The Solemnity of Mary, Mother of God Used to Mark Another Feast Day

Before the Solemnity of Mary, Mother of God, the original Octave Day was the Feast of the Circumcision of Christ. Apparently, Church leaders thought it fitting that this Jewish tradition (and the naming of the Baby Jesus) should happen eight days after His birth.
Though it’s still observed in Anglican and Lutheran Churches, the feast day gave way to the Solemnity of Mother Mary, thanks to Pope Paul VI, who thought it more appropriate to connect Octave Day to Christ’s birth. (Read: Do Catholics Really Worship Mama Mary?)
“The purpose of the celebration is to honor the role of Mary in the mystery of salvation and at the same time to sing the praises of the unique dignity thus coming to ‘the Holy Mother…through whom we have been given the gift of the Author of life,’” he said in his 1974 apostolic exhortation, Marialis Cultus.
The Solemnity of Mary, Mother of God Was Once a Debated Topic

In the Council of Ephesus in 431 AD, Nestorius, Bishop of Constantinople, insisted that Mary was the mother of the human side of Jesus. Theologians refuted this belief, stressing that Christ had both human and divine sides, which, when combined, formed one single person. This makes Mary “Theotokos,” the Greek term for God-bearer, or the Mother of God. (Read: The Pope’s Prayer for the Immaculate Conception of Mary)