In another thread I posted a quotation that was attributed to St. Ignatius of Antioch, who allegedly wrote (c. A.D. 107-110), “He who is devout to the Virgin Mother will never be lost.” I was accused by a subscriber of fabricating it.
I didn’t fabricate it. I consulted my source, “The Apostolic Digest” (1994) only to find that the attribution wasn’t in the index of attributions, so it couldn’t be traced. I then consulted my hard copy of the Letters of St. Ignatius & the quote was nowhere to be found. I then went on-line & established that although this particular quote has often been attributed to Ignatius of Antioch, I could find no one with a correct attribution. Also, others have attributed it either to St. Irenaeus of Lyons or St. Ignatius of Loyola.
At that point I gave up. I’ll concede the point that the statement was almost certainly not written by Ignatius of Antioch, & it may be entirely spurious.
However, my original purpose was twofold-- (1) to respond to another poster’s unsupported statement that, “…another fact that speaks for itself…is the total absence (in the NT & the Apostolic Fathers) of any reference to Mary serving any significant continuing role for anyone;” & (2) to demonstrate that Catholic doctrine regarding the BV is well-grounded in the writings of the early Church Fathers. As those points are (in my view) deserving of a thread of their own, I’ll continue them here.
St. Justin the Martyr, in his First Apology (A.D. 148-155) taught that Holy Mary, as the second Eve, was as involved in the reversal of the human sin problem as the first Eve was involved in introducing sin into the world: "He (Christ) became man by the Virgin so that the course which was taken by disobedience in the beginning through the agency of the serpent, might be also the very course by which it would be put down." 
“…the very course by which it would be put down”, even if it is not explicitly specific as to exactly what that role is, it strongly implies a significant continuing role. It would be hard to imagine St. Justin’s statement as being true were there not a significant continuing role for the BV.
St. Irenaeus of Lyons, in his Against Heresies, (A.D. 180-199), also taught that Holy Mary was the second & sinless Eve: "The knot of Eve’s disobedience was loosed by the obedience of Mary. What the virgin Eve had bound in unbelief, the Virgin Mary loosed through faith." [3, 22, 4]
St. John Damascene, the last of the Greek Fathers of the Church (early to mid-700s), in his Concerning the Trisegion wrote, “O Mother of God! If I place my confidence in thee I shall be saved…for being thy client is a certainty of salvation…” He also mounts a spirited defense of the BV’s title “Mother of God” in distinction to the expression “Mother of Christ” which was urged by Nestorius.
If we reflect on this for a moment, we shall see that obviously St. John was writing in defense of an older tradition-- which Nestorius had been attempting to change.
St. John Damascene, BTW, is also the author of 3 sermons on the Annunciation of the BV. In the 1st of these he attributes various blessings to her intercession. This is certainly “a significant continuing role”. The 2d contains a detailed account of her bodily translation into heaven-- an account which he says is based on the most reliable ancient traditions. We possess no ancient refutations of his viewpoint-- as if he was merely speaking what everyone already knew.
St. Andrew of Crete, St. John’s contemporary in the late 7th & early 8th Centuries & another Greek saint, wrote, “Being thy servant, O Mary, is a surety of salvation…”
This, in a nutshell, constitutes the basis of the Catholic belief-- from the writings of the early Church Fathers-- in the continuing role of the BV in salvation.