Pope Urban IV
"Lauda Sion" is a sequence prescribed for the Roman Catholic Mass for the feast of Corpus Christi. It was written by St. Thomas Aquinas around 1264, at the request of Pope Urban IV for the new Mass of this feast, along with Pange lingua, Sacris solemniis, Adoro te devote and Verbum supernum prodiens, which are used in the Divine Office.