Gregory of Nyssa was a prominent Christian theologian and bishop in the 4th century. He was born around 335 AD in what is now Turkey and was a key figure in the development of early Christian doctrine. As a member of the Cappadocian Fathers, along with his brother Basil the Great and friend Gregory of Nazianzus, he contributed significantly to the understanding of the Trinity and the nature of God. Gregory was known for his philosophical approach to theology, emphasizing the importance of reason and experience in understanding faith. His works, including "On the Soul and the Resurrection," explored topics such as the immortality of the soul and the nature of divine love, influencing later Christian thought and mysticism.