If St Mary was sinless then how was she in need of a saviour and was she born sinless or did this occur some time later in her life? Just on a side note we also refer to the patriarch as all-holy however I doubt very much that there would be any consensus as to him being sinless...
Well, this is why Catholics believe she needed a savior, even though she was sinless:
From another thread:
Before I answer I am going to preface this with a disclaimer. I am not arguing with you! I am just answering your questions from my Catholic perspective.
First, we believe that Mary did need Christ's saving death on the Cross in order to recieve the singular gift of the immaculate conception. According to Ludwigg Ott, "Mary was also redeemed by the 'grace of Christ' but in a more perfect manner than other human beings. While these are freed from original sin present in their souls (redemptio reparativa), Mary the Mother fo the Redeemer, was preserved from contagion of original sin (redemptio praeservativa or prae-redemptio). According to the great Catholic theologian, Scotus, because God is outside of time, when Mary was conceived, he could look forward to Christ's death on the Cross, and because of the infinite merits of Christ's death, God could preserve Mary from contracting original sin. I have heard is explained like this: Christ's death saves us by pulling us out of the hole of original and personal sin
, whereas Christ's death saved Mary by never allowing her to fall in the hole in the first place.