Composed by Saint Thomas Aquinas for the Office of Corpus Christi (see CORPUS CHRISTI, FEAST OF). Including the last stanza (which borrows the words “Genitori Genitoque”—Procedenti ab utroque, Compar” from the first two strophes of the second sequence of Adam of St. Victor for Pentecost) the hymn comprises six stanzas appearing in the manuscripts Pange,