It is one of the little quirks of Marian devotion (to which I am somewhat prone ;-) ) that for every Christological festival, there is a Marian equivalent. Yin and Yang. Runaway piety in part, I admit, but there is a slightly more laudable theology behind it. It was to ensure that feminine humanity was regarded as saved as well as the masculine. This should of course, be utterly bleedin' obvious to anyone with an ounce of properly taught and understood Patristic theology. Sadly, over the centuries, the Early Church's theologians were all too frequently used to justify the virtual opposite, with female humanity regarded as more flawed, weaker, prone to sin etc. Today being the Feast of Our Lady of Sorrows (or St Mary at the Cross in the SSF office), it's worth going back to the High Medieval period when a theology that took Mary's femininity serious began to dominate the theological scene. This passage from a sermon by St Bonaventure give a flavour.
"When Christ was suffering on the Cross to purify, cleanse and redeem us, the Virgin was present. With all her heart she acquiesced to the Divine Will and accepted that the fruit of her womb be offered on the Cross as a ransom. This ransom she paid as a courageous and loving woman, filled with loving respect for God. ... The glorious Virgin paid our ransom as a courageous and loving woman filled with compassion for Christ, for the world and above all for the Christian people. ... This may make us realise that the whole Christian people has issued from the womb of the glorious Virgin."
I personally baulk at the idea of Mary paying the ransom (my Barthian training) - it was Christ on the Cross who did that. Mary shared in a unique and educative way in that offering. Her example of abiding faith under soul shattering pressure is still a powerful inspiration. I'm more into the idea of her being "Mother of the Church" - Saint Ambrose of Milan (338 – 397) 1st used the idea, calling Mary Model of the Church in light of her faith, love and complete unity with Christ and Mother of the Church because she gave birth to Christ. but at least Bonaventure spoke positively of the feminine - not perhaps what one would expect of a 13th century male Italian Franciscan Cardinal and philosopher.