The earliest known prayer to our Lady is found first in a Greek Papyrus from around the year 200.
The Latin text which most Catholics will know either in the Latin or in a vernacular translation can be rendered:
We fly to [really 'beneath'] thy protection, O Holy Mother of God; despise not our petitions in our necessities, but deliver us from all dangers, O ever [the 'ever' should really go with 'deliver us'] glorious and blessed Virgin.
The Greek in the papyrus could be rendered thus:
We flee beneath thy mercy, O Mother of God; do not overlook our petitions in necessity, but deliver us from danger, O only Chaste, only Blessed.
You will notice that 'protection' was originally* compassionate mercy, eusplagnia. The root here is a word literally meaning 'bowels', seen as the seat of feeling, of compassion. When the Synoptic writers say that "Jesus had compassion upon ... ", this is the root they are employing. The Apostles sometimes beg their converts to show eusplagnia to each other. And the word for 'deliver' is the same one that we have at the end of the our Father. The prayer, in other words, is thoroughly biblical in its language, and the writer is clearly familiar with the Lucan narrative in which our Lady is Blessed, eulogemene. It is interesting to note how, well before the Council of Ephesus, it seems natural to call our Lady Mother of God.
It might seem odd to call our Lady only [mone] chaste. And other women might also qualify as blessed. I take it that the sense is that Mary is in quite a different league from other chaste and blessed women. Perhaps the point is that our Lady's chastity reaches deeply into her being so as to protect her from the sensual corruptions of the Enemy. If so, it is a witness to her Immaculate Conception.
Indeed, it is the very elevation assigned to the Mother of God that made the first modern editor of the rediscovered text misrepresent the date of this lovely prayer.
* Logically, of course, the Latin and the Greek might both come from a lost common archetype ...