Basil was born into the wealthy family of Basil the Elder, a famous rhetor, and Emelia around 330 in Caesarea Mazaca in Cappadocia (now known as Kayseri, Turkey). It was a large household, consisting of ten children, the parents, and Basil's grandmother, Macrina the Elder. His parents were known for their piety, and his maternal grandfather was a Christian martyr, executed in the years prior to Constantine I's conversion. Four of Basil's siblings are known by name, and considered to be saints by various Christian traditions. His older sister Macrina the Younger was a well-known nun. His older brother Peter served as bishop of Sebaste in Armenia, and wrote a few well-known theological treatises. His brother Naucratius was an anchorite, and inspired much of Basil's theological work. Perhaps the most influential of Basil's siblings was his younger brother Gregory. Gregory was appointed by Basil to be the bishop of Nyssa, and he produced a number of writings defending Nicene theology and describing the life of early Christian monastics.
Shortly after Basil's birth, the family moved to the estate of his grandmother Macrina, in the region of Pontus. There, Basil was educated in the home by his father and grandmother. He was greatly influenced by the elder Macrina, who herself was a student of Gregory Thaumaturgus. Following the death of his father during his teenage years, Basil returned to Caesarea in Cappadocia around 350-51 to begin his formal education.There he met Gregory of Nazianzus, who would become a lifetime friend. Together, Basil and Gregory went on to study in Constantinople, where they would have listened to the lectures of Libanius. Finally, the two spent almost six years in Athens starting around 349, where they met a fellow student who would become the emperor Julian the Apostate.It was at Athens that he began to first think about living a life focused on Christian principles.
Returning from Athens around 355, Basil briefly practiced law and taught rhetoric in Caesarea. A year later, Basil's life would change radically after he encountered Eustathius of Sebaste, a charismatic bishop and ascetic.
Basil soon abandoned his legal and teaching professions in order to devote his life to God. Describing his spiritual awakening in a letter, Basil said:
||I had wasted much time on follies and spent nearly all of my youth in vain labors, and devotion to the teachings of a wisdom that God had made foolish. Suddenly, I awoke as out of a deep sleep. I beheld the wonderful light of the Gospel truth, and I recognized the nothingnes of the wisdom of the princes of this world.|