The Orthodox Church calls the Blessed Virgin Mary Theotokos , the hidden mystery from eternity unknown by angels.St Ignatius says that the ruler of this world did not knew the Virginity of Mary , the birth of Christ from her and the death of Jesus.Three big mysteries accomplished in the silence of God.The person of the BVM is bound in the iconomy of Salvation to Jesus Christ as we confess in the creed : "Who for us men and for our salvation came down from heaven and was incarnate of the Holy Spirit and the Virgin Mary, and became man". Because of this the praise of the Mother of God has bound roots with our Saviour Jesus Christ.
The Holy Fathers starting with those from the postapostolic age untill the VIII century developed an unitarian teaching about the Virgin Mary, specifying the theological and liturgical aspects of her praise showing the help the BVM gives to the faithfull in the iconomy of salvation.
In the postapostolic time, the teology concerning Theotokos is less reacher, in exchange apologetics of high reputation such as Justin Martyr,St Iraeneus, Tertullian,Clement of Alexandria , Origen put the basics of the orthodox teachings concerning VM , highlighting the real birth of the Lord,the virginity of Theotokos and her motherhood.
The teaching about the Mother of the Lord , becomes more profound in the writings of the Church Fathers from IV-V centuries when 19 fathers and church writers of reputation from east and west bring their testimonies about the Mother of God.Father like Athanasius the Great , Chirill of Jerusalem,Basil the Great,Gregory the Theologian,Gregory of Nyssa , John Chrysostomus,Ephrem the Sir,Ambrose , Chirill of Alexandria , Leon the Great, Blessed Jeronim and Augustin.This period it`s in climax in the 3rd Ecumenical Council in Ephesus(431) when they decided the name for the Virgin Mary , Theotokos(God-bearer).
This is translated by myself from a romanian orthodox book:Adrian Lucian Dinu , The Mother of God in the Theology of the Church Fathers.
On this age(IV-V century) the devotion to Theotokos grew more and more , and this is maybe the golden era of the Church, with great Theologians like Chrysostomus , Basil the Great , Athanasius the Great, Chiril of Alexandria , Leon the Great , Ambrose , Augustin.We see that already in this age , the devotion to Mary was very big , we see that by looking at the writings of this fathers , many hymns and poetries to the Mother of God are from even then, and nice poetical theology , the honey of orthodoxy.We see that the Church Father had high esteem to the Blessed Mother of our Lord, and honour her with poetries and hymns, one of this is Ephrem the Syr , who has very beautifull poetries and praises about Mary, in the contrast of Mariology.