In case anyone appreciates this, we in the Orthodox Church also celebrate with great prominence this ancient feast, despite not using the term "Immaculate" in any official sense, we do not deny the profound holiness of our Blessed Virgin Mother of God;s conception. In our Roman Rite Mission we use this Sequence in it's traditional role, here is an english singable interpretation which, though not perfect in metre, conveys quite closely the meaning of the original latin words. May this lead to much of her grace to us in preparation for Our Lord Jesus Christ's birth!