Rule of Saint Benedict in the context of "Benedictines"

The Benedictines, officially the Order of Saint Benedict (Latin: Ordo Sancti Benedicti, abbreviated as O.S.B. or OSB), are a mainly contemplative monastic order of the Catholic Church for men and for women who follow the Rule of Saint Benedict. Initiated in 529, they are the oldest of all the religious orders in the Latin Church. The male religious are also sometimes called the Black Monks, especially in English speaking countries, after the colour of their habits, although some, like the Olivetans, wear white. They were founded by Benedict of Nursia, a 6th-century Italian monk who laid the foundations of Benedictine monasticism through the formulation of his Rule. Benedict's sister Scholastica, possibly his twin, also became religious from an early age, but chose to live as a hermit. They retained a close relationship until her death.

Despite being called an order, the Benedictines do not operate under a single hierarchy. They are instead organized as a collection of autonomous monasteries and convents, some known as abbeys. The order is represented internationally by the Benedictine Confederation, an organization set up in 1893 to represent the order's shared interests. They do not have a superior general or motherhouse with universal jurisdiction but elect an Abbot Primate to represent themselves to the Vatican and to the world.

The Cistercians (/sɪˈstɜːrʃənz/), officially the Order of Cistercians (Latin: (Sacer) Ordo Cisterciensis, abbreviated as OCist or SOCist), are a Catholic religious order of monks and nuns that branched off from the Benedictines and follow the Rule of Saint Benedict, as well as the contributions of the highly influential Bernard of Clairvaux, known as the Latin Rule. They are also known as Bernardines, after Saint Bernard, or as White Monks, in reference to the colour of their cowl, as opposed to the black cowl worn by Benedictines.

The term Cistercian derives from Cistercium, the Latin name for the locale of Cîteaux, near Dijon in eastern France. It was here that a group of Benedictine monks from the monastery of Molesme founded Cîteaux Abbey in 1098. The first three abbots were Robert of Molesme, Alberic of Cîteaux and Stephen Harding. Bernard helped launch a new era when he entered the monastery in the early 1110s with 30 companions. By the end of the 12th century, the order had spread throughout most of Europe.

The English Benedictine Reform or Monastic Reform of the English church in the late tenth century was a religious and intellectual movement in the later Anglo-Saxon period. In the mid-tenth century almost all monasteries were staffed by secular clergy, who were often married. The reformers sought to replace them with celibate contemplative monks following the Rule of Saint Benedict. The movement was inspired by Continental monastic reforms, and the leading figures were Dunstan, Archbishop of Canterbury, Æthelwold, Bishop of Winchester, and Oswald, Archbishop of York.

In seventh- and eighth-century England, most monasteries were Benedictine, but in the ninth century learning and monasticism declined severely. Alfred the Great (871–899) deplored the decline and started to reverse it. The court of Æthelstan (924–939), the first king of the whole of England, was cosmopolitan, and future reformers such as Dunstan and Æthelwold learned from Continental exponents of Benedictine monasticism. The English movement became dominant under King Edgar (959–975), who supported the expulsion of secular clergy from monasteries and cathedral chapters, and their replacement by monks. The reformers had close relations with the Crown, furthering its interests and depending on its support. The movement was confined to southern England and the Midlands, as the Crown was not strong enough in northern England to confiscate property from local elites there to establish Benedictine foundations. The movement declined after the deaths of its leading exponents at the end of the tenth century.

The Olivetans, formally known as the Order of Our Lady of Mount Olivet, are a monastic order. They were founded in 1313 and recognised in 1344. They use the Rule of Saint Benedict and are a member of the Benedictine Confederation, where they are also known as the Olivetan Congregation, but are distinguished from the Benedictines in their white habit and centralized organisation. They use the post-nominals 'OSB Oliv'.