Basilian monks are monks who follow the "Rule" of Saint Basil the Great, bishop of Caesarea (330-379). The monastic rules and institutes of St. Basil are important because their reconstruction of monastic life remains the basis for most Eastern Orthodox and some Greek Catholic monasticism. Saint Benedict of Nursia, who fulfilled much the same function in the West, took his Regula Benedicti from the writings of St. Basil and other earlier church fathers. In the Eastern Orthodox Church, monks do not generally call themselves "Basilians", while the Greek Catholics do. Thus the expression "Basilian monk" almost always refers to religious of those Eastern Catholic Churches which follow the Byzantine Rite.
Under the name of Basilians are included all the religious that follow the Rules of St. Basil. It should be noted that the "Rules" of St. Basil are not intended to be constitutions like the various Western monastic Rules; rather, it is a collection of his responses to questions about the ascetic life—hence the more accurate original name: Asketikon. There were two such collections, the Greater Asketikon and the Lesser Asketicon (the difference between the two being their length).
Basil of Caesarea, also called Saint Basil the Great (Greek: Ἅγιος Βασίλειος ὁ Μέγας, Ágios Basíleios o Mégas; 329 or 330 – January 1 or 2, 379), was the Greek bishop of Caesarea Mazaca in Cappadocia, Asia Minor (modern-day Turkey). He was an influential theologian who supported the Nicene Creed and opposed the heresies of the early Christian church, fighting against both Arianism and the followers of Apollinaris of Laodicea. His ability to balance his theological convictions with his political connections made Basil a powerful advocate for the Nicene position.
In addition to his work as a theologian, Basil was known for his care of the poor and underprivileged. Basil established guidelines for monastic life which focus on community life, liturgical prayer, and manual labour. Together with Pachomius, he is remembered as a father of communal monasticism in Eastern Christianity. He is considered a saint by the traditions of both Eastern and Western Christianity.
Basil, Gregory of Nazianzus, and Gregory of Nyssa are collectively referred to as the Cappadocian Fathers. The Eastern Orthodox Church and Eastern Catholic Churches have given him, together with Gregory of Nazianzus and John Chrysostom, the title of Great Hierarch. He is recognised as a Doctor of the Church in the Roman Catholic Church. He is sometimes referred to by the epithet "Ουρανοφαντωρ" (Ouranofantor), "revealer of heavenly mysteries".