Te Deum (Thee, O God), a grand hymn in Latin, so called from the first words, sung at matins and on occasions of joy and thanksgiving; of uncertain authorship; is called also the Ambrosian Hymn, as ascribed, though without foundation, to St. Ambrose; is with more reason seemingly ascribed to Hilary, bishop of Aries.
Definition taken from The Nuttall Encyclopædia, edited by the Reverend James Wood (1907)
Taylor Institute * Teazle, Lady