Basil of Caesarea; also called Saint Basil the Great; (330 - January 1; 379); was the bishop of Caesarea Mazaca in Cappadocia; Asia Minor (modern-day Turkey). He was an influential 4th century Christian theologian and monastic. Theologically; Basil was a supporter of the Nicene faction of the church; in opposition to Arianism on one side and the followers of Apollinaris of Laodicea on the other. 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 labor. 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. The Eastern Orthodox Church and the Roman Catholic Church have also named him a Doctor of the Church. He is also referred to as "the revealer of heavenly mysteries" (Ouranophantor).