“TU TRINITATIS UNITAS.” – Hymn of the Lauds for Friday, by an unknown author of the 5th century. It is found in manuscripts of the 9th century.
It is both a profession of faith and a song of love to the Trinity of divine Persons who, in their mysterious unity, govern and direct the world.
Bibl.: G. S. Piment, Les hymnes du Bréviaire romain, I. Paris 1874, pp. 242-49; F. Vanderstuyf, Les hymnes de l'Ordinaire du Bréviaire, Paris 1912, p. 100; A. Mirra, Gli inni del Breviario romano, Naples 1947, p. 74. Silverio Mattei