Nocturns (Latin: Nocturni or Nocturna) or the Night Office is the part of the Christian Liturgy of the Hours said during the night after sleeping and before Lauds at sunrise. It was considered part of Matins. A nocturn consists of psalms with antiphons followed by three lessons, which are taken either from scripture or from the writings of the Church Fathers. The office of Matins is composed of one to three nocturns. The term nocturn has been used since Late Antiquity. In 1970, following the Second Vatican Council, a revision of the Roman Breviary discontinued the use of nocturns when the office of Matins was reformed as the Office of Readings.
Tertullian speaks of nocturnal gatherings; St. Cyprian, of the nocturnal hours, "nulla sint horis nocturnis precum damna, nulla orationum pigra et ignava dispendia". In the life of Melania the Younger is found the expression "nocturnæ horæ", "nocturna tempora". In these passages the term signifies night prayer in general and seems synonymous with the word vigiliæ.
Nocturnes arose from the custom of primitive Christians holding their assemblies at night. In the ancient church, a vigil, or all-night watch service, preceded every Sunday, consisting of evening, night, and early morning prayers. By the fourth century this Sunday vigil had become a daily observance, though it no longer lasted throughout the night. The Office of the Vigils, and consequently of the Nocturns, was a single Office, recited without interruption at midnight. What had at first been an all-night vigil became a watch service only from cock crow to sunrise with a preliminary office at the lighting of the lamps the night before. This last evolved into Vespers.