On September 8th, we celebrated Mary's Nativity, and soon, on December 8th, we will celebrate her Immaculate Conception.
The Gospels do not tell us where Mary was born but the proto-gospel of James—originally called "The Nativity of Mary"—mentions a house in Jerusalem called "Anne's House." A church was built near this house and it was consecrated on September 8th (year unknown). The feast of that dedication then extended to Constantinople in the fifth century, and to Rome and the West in the 7th century. Logically, the feast of her conception was celebrated nine months earlier, hence the date of December 8th.
The Nativity of Mary was an important feast in the Eastern Churches. It is actually the first great feast of the cycle of saints’ feasts in the liturgical year. The readings and prayers for that day put in a perfect light the meaning of the Church's veneration of Mary.
Pope Saint John Paul II said during the general audience of September 8, 2004: "This feast, very important to popular piety, leads us to admire in Mary the child, the purest dawn of the Redemption. We are contemplating a little girl like every other, yet at the same time the only one who was blessed among women" (Lk 1: 42).
The Polish pontiff also drew a parallel between the cradle of the child Mary and the duty of every person to "protect and defend the fragile creatures" that are children.
Adapted from Vatican News