"This processional Hymn for Palm Sunday is said to nave been composed by S. Theodulph at Metz, or as others will have it, at Angers, while imprisoned on a false accusation: and to have been song by him from his dungeon window, or by choristers instructed by him, as the Emperor Louis and his Court were on their way to the Cathedral. The good Bishop was immediately liberated. In the original composition there were ten stanzas besides the Chorus."
—"Gloria, laus, et honor" in Mediaeval Hymns and Sequences (ed.) by John Mason Neale (1867).