Why, people ask, was January 1 deprived of its old name of the Feast of the Circumcision? Since it manifestly is eight days after the Nativity, and eight days after His birth was when the Lord was circumcised.
The question is a mere detail. In the Gregorian Sacramentary, today was called simply the Octave of the Lord, and its Collect (as today) concerned the Mother of God (Deus qui salutis aeternae). (The Byzantine Rite also has a natural inclination to concentrate on an aspect of a great feast on a nearby day). During the Middle Ages, today came to have the title of the Circumcision, but the propers were not changed. So even while it was called the Feast of the Circumcision, most of the Mass and Office (except for the Gospel and some readings at Mattins), did not have any reference to the Circumcision. They were about the Incarnation, our Lady's part in it, and her perpetual Virginity.
At Lauds, the first Antiphon (O admirabile commercium) is a superb reminder that the Incarnation of God makes us, the baptised, into Gods (or, to be pedantic, sharers in the Godhead of the one into whom we have been baptised). What a wonderful Swap (commercium)! The Creator of the human race, taking an animated body, has deigned to be born of a Virgin, and, going forth as a human without seed, has granted to us his Divinity. The second antiphon typologically uses the dew that fell upon Gideon's flece; the third sees the bush that was burned but not consumed as a type of Mary's virginity, undiminished by her childbearing.
Personally, I feel that the simplest and best title is that of Octave of the Nativity; surely we could call it that and then leave the unchanged ancient texts to make their own different but interrelated points. I suspect the post-Conciliar tamperers changed it to Mary Mother of God simply to give themselves an excuse for suppressing Pius XI's feast on October 11. (And it would be jolly to start rescuing the term Octave from practical oblivion.)
Mutual Enrichment ... Dom Anselmo Lentini, in the Liturgia Horarum, mandated by the Council to increase the use of ancient hymnody drawn from the vast treasury of the Latin Church, introduced the fine Prudentian hymn Corde natus ex Parentis [Of the Father's Heart begotten] as an Office Hymn for today. A marvellous idea. I love so much of its phraseology ... Corde natus ... ipse fons et clausula ... as well as those great striding trochaic tetrameters catalectic. A mature and glorious moment in the evolution of Christian Latin. (What a Diabolical scandal that, within a decade of Sacrosanctum Concilium, its provisions [especially paras 93 and 101] were so brazenly suppressed in order to eliminate a latinate and literate clergy connected to their roots ... as part of a wider conspiracy frankly revealed by Screwtape at the end of Chapter XXVII.)
Hymns are a weak point in the 1961 Breviary; their texts still stand as they were corrupted by Urban VIII, and more variety is surely needed. Is there any cleric who really enjoys saying Iste Confessor day after day? It will be a great day when, on both 'sides', we have a sufficiently balanced, relaxed, and distanced view of Vatican II and its aftermath to be able to incorporate some of their worthier elements into our incomparable ancient rites.