O lux beata Trinitas

O lux beata Trinitas. Latin, author unknown. This hymn was attributed to Ambrose of Milan* in JJ (p. 842), and it is one of the hymns under Ambrose’s name in Daniel, Thesaurus Hymnologicus I. 36-7. Daniel’s note (TH IV. 47-8) quotes Hincmar of Rheims, De una et non trina Deitate, as ascribing it to Ambrose, and quotes from a letter of Ambrose (Epist. 21) which says that the people of Milan daily proclaimed their faith by singing his Trinitarian verses; but A.S. Walpole (Early Latin Hymns, no. 79, p. 290) argued that other hymns have Trinitarian material, and that Ambrose was referring to one of those. It is not in the Milanese rite, and it is now thought not to be by him. It was included in...