According to tradition, Bishops on their way to the Council of Ephesus convened at the Sanctuary of Our Lady at Mellieħa. Whether the Malta visit happened before or after Ephesus is unclear, but documentary evidence in the form of a stone fragments and more importantly, the iconography of the Sanctuary, affirms the tradition (Figure 1).
The third ecumenical council held in Ephesus in A.D. 431, was an attempt to retain doctrinal boundaries set by earlier councils whose integrity was being threatened by the teachings of Nestorius, Patriarch of Constantinople. Nestorius proclaimed that the Blessed Virgin should be titled Christotokos ("she who has begotten Christ") rather than Theotokos ("she who has begotten God"); the latter being a term that had begun to be used by Egyptian Christians in the third century. The Bishops met in June and July A.D. 431 at the Church of Mary in Ephesus in Anatolia and subsequently declared Mary Mother of God .
In a letter published in L'Osservatore Romano on 4 December 1996, Pope John Paul II (who incidentally prayed at the Sanctuary in May 1990, see Figure 9), shines light on the chronos of Marian dogma:
In the first Christian community, as the disciples became more aware that Jesus is the Son of God, it became ever clearer that Mary is the Theotókos, the Mother of God. This is a title which does not appear explicitly in the Gospel texts, but in them the "Mother of Jesus" is mentioned and it is affirmed that Jesus is God (Jn 20:28; cf. 5:18; 10:30, 33). Mary is in any case presented as the Mother of Emmanuel, which means "God with us" (cf. Mt 1:22-23).In the bema of the Sanctuary, four unsigned paintings thought to date back to the 18th Century celebrate the life of Mary as she appears in scripture.
Figure 1: Convening Bishops on domed roof above the Ascension (left)
and Marriage (right) of Our Lady.
Figure 2: The Marriage of Our Lady and Saint Joseph with High Priest in
attendance. Joseph's rod blossoms 
|Figure 3: The Annunciation, oil on canvas|
|Figure 4: The Ascension of Our Lady, oil on canvas|
Figure 9: Holy Communion and a Wedding
Figure 10: A nun clears the conciliar
Altar after mass
http://www.ewtn.com/library/papaldoc/jp2bvm37.htm (accessed 27th August 2013)
 Gospel of Pseudo-Matthew
http://www.newadvent.org/fathers/0848.htm (accessed 27th August 2013)