It is true that the Fourth Council of Toledo (a.d. 633) in its 13th canon couples Hilary with Ambrose as the writer of hymns in actual use. But these canons are verbose productions, and this may be a mere literary flourish, natural enough in countrymen and contemporaries of Isidore of Seville, who knew, no doubt from Jerome’s Viri Illustres, that Hilary was the first Latin hymn writer.