I don't hold Pope Urban VIII (A.D 1568-1644) in very high esteem, but he was no idiot. He knew the Latin language inside out, and indeed composed some of his own hymns which, lamentably, in 1629 were incorporated into the Roman Breviary. I find it astounding that in this respect he did not conform to the old Roman tradition but to an absurd, pseudo-Classical Latinity, which is of course not traditional but a gross anachronism (what on earth does Olympus have to do with the Faith?!), aimed at meeting his own tastes, and the general taste of his age. Are these the early signs of aggiornamento, which Tolkien said in 1963 was fraught with danger? He had the aid of four Jesuits, a small committee. I think that Jesuits and Liturgy have seldom got on precisely because of the unique apostolate of this Counter-Reformation Order - reciting the Office alone on Mission, saying Low Mass alone, again on Mission. Liturgy should never have become a solitary act (as a missionary Order, I like the idea of the Jesuits, a well-trained, highly intelligent Order of Priests - shame it never really worked out in the end. I have met one good Jesuit in my life, and know of one other), and despite all the ''theology'' you might try to scaffold around Low Mass, all the choirs of Angels rejoicing in the Sacrifice celebrated by a lonely priest etc, Liturgy is supposed to mirror the Heavenly liturgy as much as possible in a tangible way - for example, the presence of Sacred Ministers, a liturgical choir, incense, servers etc. Low Mass falls short of this. Anyway, I digress as usual. These hymns are entirely repugnant to the liturgical Tradition of the Roman Rite and represent yet more Papal interference in the florid sequence of liturgical growth. Did Urban VIII spurn the kind of Latin used by St Ambrose, St Augustine and St Leo the Great? Surely you agree that using Papal authority to alter the Liturgy is an abuse?
Of the Breviary reform of Urban VIII, that great and erudite scholar Fr Adrian Fortescue had this to say: ''No one who knows anything about the subject now doubts that the revision of Urban VIII was a ghastly mistake, for which there is not one single word of any kind to be said.'' (Adrian Fortescue, Concerning Hymns, p.37). Luckily those who were exempt from the revision, taking advantage of the antiquity of their own liturgical books, avoided the new Breviary (the Benedictines, the Cistercians, the Dominicans etc), and one good thing, coming out of Vatican II as a rose from a dung-heap, is that the older hymns were brought back. This is not to say, however, that I approve of the liturgia horarum.
While we're on the subject, let's say a few words about the correct pronunciation of Latin. I learned Classical Latin, and certainly it is more traditional to pronounce Latin in the Classical way. It was only under Pius X that the Italian way was imposed on the Universal Church - another example of Papal authority going beyond its constraints. You don't honestly think that some parish priest in England circa 1150 pronounced Latin as they did in the Papal court? There is every reason not to pronounce Latin in the Italian fashion; it just goes against the grain in Northern Europe. I would personally argue from both an historical and aesthetic perspective. An example: which sounds nicer? Sancta Caecilia, ora pro nobis [Classical style: sanc-ta kai-keel-ia, ora pro no-bees], or Sancta Caecilia, ora pro nobis [''ecclesiastical'' fashion: sanc-ta chae-chee-lee-a, ora pro no-bees].
But to what extent would this affect Sacred Music I wonder?...