Basil of Caesarea, also called Saint Basil the Great (330 – January 1 or 2, 379), was the 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 labor. Together with Pachomius, he is remembered as a father of communal monasticismin 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 recognized as a Doctor of the Church in the Roman Catholic Church. He is sometimes referred to by the epithet Ouranophantor, "revealer of heavenly mysteries".

Source: https://en.wikipedia.org/wiki/Basil_of_Caesarea

            St. Basil the Great - c. 364 A.D.
On the Holy Spirit St. Basil the Great - c. 368 A.D.
Nine Homilies of Hexaemeron     
                                          St. Basil the Great - c. 365 A.D.
Letters