Source: Fr Lawrence Farley's Blog
When Mary of Nazareth first emerged from her mother as a newborn infant and uttered her first newborn cries, few then present could have had any inkling what that child would mean to human history.
Fr Thomas Hopko teaches about the Feast of the Nativity of the Theotokos by looking at the hymnology associated with the feast
The first great liturgical celebration, Church feast, of the ecclesiastical year that begins in September in the Orthodox Church is the festival of the Nativity, the birthday of the Virgin Mary, of Christ’s mother, the Theotokos, Virgin Mary. This festival is on the 21st of September.
It’s fitting that the very first great feast of the Church year would be Mary’s birthday especially as we recall that the last great festival of the ecclesiastical year in August is Mary’s entrance into eternal life; her kimesis, her falling asleep, her dormition. So we end the year with the Dormition of Mary and we begin the year with the birth of Mary.