September 8 - Feast of the Nativity of the Virgin

While no one knows the exact date of the Virgin Mary's birth, it has been celebrated as a feast day since the sixth century.  The cult of the virgin probably began in Syria and the feast came out of that tradition.  Mary's immaculate conception, her life as the mother of Christ led theologians to develop a parallel between the Passion of Christ and the compassion of Mary:  as he suffered and died on the cross, she was crucified in spirit.