This hymn text was written by St. Theodulph of Orleans in 820 while he was imprisoned in Angers, France, for conspiring against the King, with whom he had fallen out of favor. The text acts as a retelling of the triumphal entry of Jesus into Jerusalem. The medieval church actually re-enacted this story on Palm Sunday using a standard liturgy that featured this hymn. The priests and inhabitants of a city would process from the fields to the gate of the city, following a living representation of Jesus seated on a donkey.