Her Foot Has Crushed The Head of Satan?

Pope Pius IX (Pio Nono) on Mary in his encyclical Ubi primum:

“The resplendent glory of her merits, far exceeding all the choirs of angel, elevates her to the very steps of the throne of God.  Her foot has crushed the head of Satan.  Set up between Christ and his Church, Mary, ever lovable, and full of grace, always has delivered the Christian people from their greatest calamities and from the snares and assaults of all their enemies, ever rescuing them from ruin.”