The Church knows very little about the birth of the Blessed Virgin Mary. The Gospels do not provide any information on the birth of Mary. When we first meet the Blessed Virgin Mary in the Gospels of St. Matthew and St. Luke, Mary is presented as a virgin who is espoused to a man named Joseph.
The early Church, especially in the East, had a deep devotion to the Blessed Virgin Mary, because she was the Mother of Our Lord. Out of this devotion grew legends of her parents and her early life, including her birth. It is from these early devotions and legends that the Church now acknowledges St’s. Anne and Joachim as Mary’s parents. As often is the case in the Old Testament, our legends tell of Anne and Joachim as being somewhat advanced in age, childless and ardent in their devotion to God. They long for a child and God abundantly answers their prayers through the birth of the Blessed Virgin Mary.
The feast of the Immaculate Conception of Mary was celebrated, in the East, as early as the 5th century. It is from this feast that we fix the date for the celebration of the Nativity of Mary, which began in the 6th century. The feast of the Immaculate Conception is celebrated on December 12, hence a September 8th date, nine months later, for the feast of the birth of the Blessed Virgin Mary.
We celebrate this feast because Mary’s birth is important to the Church. It is through Mary that we “receive” our Lord and Savior Jesus Christ. It is Mary’s birth that sets the stage for the salvation of mankind. Interestingly, the Church only celebrates three births within the liturgical year: the birth of Jesus Christ, our Lord and Savior; the birth of St. John the Baptist, the precursor; and, the birth of Mary, the Mother of God.