"Puer nobis nascitur", usually translated as "Unto Us Is Born a Son", is a medieval Christmas carol found in a number of manuscript sources—the 14th-century German Moosburg Gradual and a 15th-century Trier manuscript. The Moosburg Gradual itself contained a number of melodies derived from the 12th- and 13th-century organum repertories of Notre Dame de Paris and the Abbey of Saint Martial, Limoges, suggesting that its antiquity may be much greater.