Gregory of Nyssa (c. 335–c. 394), or Gregory Nyssen as he is also known, was born in Neocaesarea, Pontus, now known as the Black Sea region of Turkey. He is considered a saint by most liturgical churches, such as Roman Catholic, Eastern Orthodox, and Lutheran, but not on par with the more highly acclaimed church fathers such as St. Jerome. Gregory of Nyssa served as a bishop of the church from 372 to 376 and from 378 until his death. He is best known for his contributions to the Christian understanding of the Trinity and for his work in defending the Nicene Creed.
Gregory’s early education was at home. Any higher education is unknown, although Gregory stated that his only education came from his older brother Basil and “Paul, John, and the rest of the apostles and prophets” (quoted by Morwenna Ludlow in Universal Salvation: Eschatology in the Thought of Gregory of Nyssa and Karl Rahner, Oxford University Press, 2000, p. 21). He initially pursued a career as a public speaker and may have married a woman named Theosebia, but this is speculation as very little is known of his early years.
In AD 372 Gregory was elected bishop of Nyssa, a position his brother, Basil of Caesarea, helped champion for him. Gregory was not a good administrator, however, and that led to his dismissal as bishop by Emperor Valens in 376. Gregory was reinstated by Emperor Gratian in 378.
Together with their friend Gregory of Nazianzus, Gregory and Basil became known as the Cappadocian Fathers. They pursued their passion of helping people understand the Trinitarian nature of God, as well as fighting against Arianism, which called into question the divine nature of Jesus Christ. The three Cappadocian Fathers crystalized the orthodox view of the Triune Godhead, writing with clarity and precision in defense of One God with one substance in three Persons. Partly through the work of Gregory, Gregory, and Basil, Arianism was finally defeated at the Council of Constantinople in 381.
Gregory of Nyssa wrote persuasively and prolifically on theological topics that greatly influenced the direction of the fourth-century church. Gregory’s writing tended toward Christian mysticism and asceticism. Some of his most noteworthy works are The Life of Moses, On the Work of the Six Days, Against Eunomius, and Great Catechism. His philosophies are difficult to categorize as he leaned toward Neoplatonism (a system of thought derived from Plato and expanded upon by other philosophers) for his understanding of the Trinity, and he espoused universal salvation as supported by Origen.
Although his life and work were respected far more in the Eastern churches than in Western branches of Christianity, Gregory of Nyssa is still venerated by Roman Catholic Church as a saint and honored on January 10, in memory of the day he died.