Apart from the breviary and missal Latin hymns, the finest I know, of which the inspiration is Catholic doctrine, are those of Father Robert Southwell, the Jesuit martyr. I often wish some of our excellent Catholic magazines, on both sides of the Atlantic, would reproduce some of them instead of ' original' Catholic poetry. Of one of them Ben Jonson said that he would willingly have burnt much of his own work if it could have given him the authorship of that poem.
As for Milton's most glorious ode and hymn, ' On the Morning of Christ's Nativity,' I would give all' Paradise Lost' and all' Paradise Regained' for it. It is as exquisite as Perugino's ' Prophets and Sibyls,' with the super-added stateliness and majesty of Michelangelo.
Link (here) to the portion of the book entitled Pages from the Past, by famous English Catholic prelate and writer John Ayscough. More literary works by Ayscough are; French Windows, Catesby's Story, John Ayscough's Letters to his Mother and Discourses and Essays