September 8 is the feast of the birth of Mary. We don't know much about her early life that can be historically verified. But there's an interesting document called the Gospel of James that gives details about Mary's birth. This book is not one of the canonical Gospels, so it's not a source of faith and we can't rely on it for history. But it dates to around the early second century, and it shows that even then, people were interested in finding out about Mary. This book is where we get some of the details about Mary's life that have been part of tradition, such as the names of her parents (Joachim and Anne). This book also has a strong emphasis on Mary's virginity. Again, this shows how ancient this belief is.
In his homily on the recent feast of the Assumption, Pope Benedict said, "Mary lived on the Word of God, she was imbued with the Word of God. ... Whoever thinks with God thinks well, and whoever speaks to God speaks well."