"One of the finest of the mediaeval Latin hymns [...] It was written for the office of the Festival of Corpus Christi, which St. Thomas drew up in 1263, at the request of Pope Urban IV. The metre and the opening line are imitated from Fortunatus. [...] Wherever employed it was always primarily for use on Corpus Christi, either at Matins (Sarum) or at Vespers (Roman). It has also been used as a processional on Corpus Christi, in the Votive Office of the Blessed Sacrament, at the Forty Hours, and otherwise. Stanza v., 'Tantum ergo sacramentum', with the magnificent doxology, is sung as a separate hymn in the office of the Benediction of the Blessed Sacrament, or during Mass at the Elevation of the Host." —"Pange lingua gloriosi corporis mysterium," by William Arderne Shoults in A Dictionary of Hymnology, (ed.) by John Julian (1892).
