The four-voice Lauda Sion was included in Palestrina’s Motecta festorum totius anni quaternis vocibus of 1563, his first, widely successful book of motets. Based on a 13^th century sequence by St. Thomas Aquinas, this hymn of quiet thanksgiving celebrates the miraculous nature of the feast of Holy Communion. The tune or cantus prius factus is sonically present throughout, concluding with a final Amen.  This motet becomes the basis for Palestrina’s Missa Lauda Sion of 1582.