Gregory was born of a deeply religious family, not very rich in worldly goods, to which circumstances he probably owed the pious training of his youth. His mother Emmelia was a martyr's daughter; two of his brothers, Basil of Cæsarea and Peter of Sebaste, became bishops like himself; his eldest sister, Macrina, became a model of piety and is honored as a saint. Another brother, Naucratius, a lawyer, inclined to a life of asceticism, but died too young to realize his desires. A letter of Gregory to his younger brother, Peter, exhibits the feelings of lively gratitude which both cherished for their elder brother Basil, whom Gregory calls "our father and our master".

Being the older brother, Basil to supervised the education of his younger brothers. Basil's training was an antidote to the lessons of the pagan schools, wherein, as we know from a letter of St. Gregory of Nazianzus, Gregory of Nyssa spent some time, very probably in his early youth, for it is certain that while still a youth Gregory exercised the ecclesiastical office of rector.

His family, it would seem, had endeavored to turn his thoughts towards the Church, for when the young man chose a secular career and began the study of rhetoric, Basil remonstrated with him long and earnestly; when he had failed he called on Gregory's friends to influence him against that objectionable secular calling. It was all in vain; moreover, it would seem that the young man married. There exists a letter addressed to him by Gregory of Nazianzus condoling with him on the loss of one Theosebeia, who must have been his wife, and with whom he continued to live, as with a sister, even after he became bishop. This is also evident from his treatise "De virginitate".

His birth and upbringing came at a time when the Arian disputes were at their height. Having received an excellent education, he was at one time a teacher of rhetoric. St. Gregory was an ardent advocate for Orthodoxy, and he fought against the Arian heresy with his brother St. Basil. Gregory was persecuted by the Arians, by whom he was falsely accused of improper use of church property, and thereby deprived of his See and sent to Ancyra.

In the year 372, he was consecrated by St. Basil the Great as Bishop of the city of Nyssa in Cappadocia. However, Gregory at first refused the position. The episcopal charge in that day was beset with many dangers. Moreover in the fourth century, and even later, it was not uncommon to express dislike of the episcopal honor, and to fly from the prospect of election. The fugitives, however, were usually discovered and brought back, and the consecration took place when a show of resistance had saved the candidate's humility. Whether it was so in Gregory's case, or whether he really did feel his own unfitness, we do not know.

On arriving in his see Gregory had to face great difficulties. His sudden elevation may have turned against him some who had hoped for the office themselves. It would appear that one of the courtiers of Emperor Valens had solicited the see either for himself or one of his friends. When Demosthenes, Governor of Pontus, convened an assembly of Eastern bishops, a certain Philocares, at one of its sessions, accused Gregory of wasting church property, and of irregularity in his election to the episcopate, whereupon Demosthenes ordered the Bishop of Nyssa to be seized and brought before him.

Basil seems to have regretted at times the constraint thus put on his brother, now removed from his influence. He complained about Gregory's naive and clumsy interference with his business.  In 375 Gregory seemed to him decidedly incapable of ruling a Church. At the same time he had but faint praise for Gregory's zeal for souls.

In 376 St. Gregory was again deposed in absentia by a synod of Arian bishops. Gregory at first allowed himself to be led away by his captors, then losing heart and discouraged by the cold and brutal treatment he met with, he took an opportunity of escape and reached a place of safety. Thereafter, Gregory continued to encourage his flock in Orthodoxy, wandering about from place to place.

After the death of the emperor Valens in 378, St. Gregory was restored to his cathedra and was joyously received by his flock.  The new emperor, Gratian, published an edict of tolerance, and Gregory returned to his see, where he was received with joy. A few months later in January of 379 his brother Basil died; and only with difficulty did St. Gregory survive the loss of his brother and guide. He delivered a funeral oration for him, and completed St. Basil's Study of the Six Days of Creation, the Hexaemeron.

Following the death of Basil, Gregory was engaged in an era of activity. In 379 he assisted at the Council of Antioch which had been summoned because of the Meletian schism. Soon after this, it is supposed, he visited Palestine. There is reason for believing that he was sent officially to remedy the disorders of the Church of Arabia. That same year St. Gregory participated in the Council of Antioch against heretics who refused to recognize the perpetual virginity of the Mother of God. Others at the opposite extreme, who worshipped the Mother of God as being God Herself, were also denounced by the Council. He visited the churches of Arabia and Palestine, which were infected with the Arian heresy, to assert the Orthodox teaching about the Most Holy Theotokos. On his return journey St. Gregory visited Jerusalem and the Holy Places.

In the year 381 St. Gregory was one of the chief figures of the Second Ecumenical Council, convened at Constantinople against the heresy of Macedonius, who incorrectly taught about the Holy Spirit. At this Council, on the initiative of St. Gregory, the Nicean Symbol of Faith (the Creed) was completed.

Together with the other bishops St. Gregory affirmed St. Gregory the Theologian as Archpastor of Constantinople.

In the year 383, St. Gregory of Nyssa participated in a Council at Constantinople, where he preached a sermon on the divinity of the Son and the Holy Spirit. In 386, he was again at Constantinople, and he was asked to speak the funeral oration in memory of the empress Placilla. Again in 394 St. Gregory was present in Constantinople at a local Council, convened to resolve church matters in Arabia.

St. Gregory of Nyssa was a fiery defender of Orthodox dogmas and a zealous teacher of his flock, a kind and compassionate father to his spiritual children, and their intercessor before the courts. He was distinguished by his magnanimity, patience and love of peace.

Having reached old age, St. Gregory of Nyssa died soon after the Council of Constantinople. Together with his great contemporaries, Sts. Basil the Great and Gregory the Theologian, St. Gregory of Nyssa had a significant influence on the Church life of his time. His sister, St. Macrina, wrote to him: "You are renowned both in the cities, and gatherings of people, and throughout entire districts. Churches ask you for help." St. Gregory is known in history as one of the most profound Christian thinkers of the fourth century. Endowed with philosophical talent, he saw philosophy as a means for a deeper penetration into the authentic meaning of divine revelation.

St. Gregory left behind many remarkable works of dogmatic character, as well as sermons and discourses. He has been called "the Father of Fathers."




But possibly his journey did not take place till after the Council of Constantinople in 381, convened by Emperor Theodosius for the welfare of religion in that city. It asserted the faith of Nicæa, and tried to put an end to Arianism and Pneumatism in the East. This council was not looked on as an important one at the time; even those present at it seldom refer to it in their writings. Gregory himself, though he assisted at the council, mentions it only casually in his funeral oration over Meletius of Antioch, who died during the course of this assembly.

It is very probable that Gregory was present at another Council of Constantinople in 383; his "Oratio de deitate Filii et Spiritus Sancti" seems to confirm this. In 385 or 386 he preached the funeral sermon over the imperial Princess Pulcheria, and shortly afterwards over Empress Flaccilla. A little later we meet him again at Constantinople, on which occasion his counsel was sought for the repression of ecclesiastical disorders in Arabia; he then disappears from history, and probably did not long survive this journey.

Exegetical Works
Most of his writings treat of the Sacred Scriptures. He was an ardent admirer of Origen, and applied constantly the latter's principles of hermeneutics. Gregory is ever in quest of allegorical interpretations and mystical meanings hidden away beneath the literal sense of texts. As a rule, however, the "great Cappadocians" tried to eliminate this tendency. His "Treatise on the Work of the Six Days" follows St. Basil's Hexæmeron. Another work, "On the Creation of Man", deals with the work of the Sixth Day, and contains some curious anatomical details; it was translated into Latin by Dionysius Exiguus. His account of Moses as legislator offers much fine-spun allegorizing, and the same is true of his "Explanation of the Titles of the Psalms". In a brief tractate on the witch of Endor he says that the woman did not see Samuel, but only a demon, who put on the figure of the prophet. Besides a homily on the sixth Psalm, he wrote eight homilies on Ecclesiastes, in which he taught that the soul should rise above the senses, and that true peace is only to be found in contempt of worldly greatness. He is also the author of fifteen homilies on the Canticle of Canticles (the union of the soul with its Creator), five very eloquent homilies on the Lord's Prayer, and eight highly rhetorical homilies on the Beatitudes.

Theological Works
In theology Gregory shows himself more original and more at ease. Yet his originality is purely in manner, since he added little that is new. His diction, however, offers many felicitous and pleasing allusions, suggested probably by his mystical turn of mind. These grave studies were taken up by him late in life, hence he follows step by step the teaching of St. Basil and of St. Gregory of Nazianzus. Like them he defends the unity of the Divine nature and the trinity of Persons; where he loses their guidance, our confidence in him tends to decrease. In his teaching on the Eucharist he appears really original; his Christological doctrine, however, is based entirely on Origen and St. Athanasius. The most important of his theological writings is his large "Catechesis", or "Oratio Catechetica", an argumentative defence in forty chapters of Catholic teaching as against Jews, heathens, and heretics. The most extensive of his extant works is his refutation of Eunomius in twelve books, a defence of St. Basil against that heretic, and also of the Nicene Creed against Arianism; this work is of capital importance in the history of the Arian controversy. He also wrote two works against Apollinaris of Laodicea, in refutation of the false doctrines of that writer, viz. that the body of Christ descended from heaven, and that in Christ, the Divine Word acted as the rational soul. Among the works of Gregory are certain "Opuscula" on the Trinity addressed to Ablabius, the tribune Simplicius, and Eustathius of Sebaste. He wrote also against Arius and Sabellius, and against the Macedonians, who denied the divinity of the Holy Spirit; the latter work he never finished. In the "De anima et resurrectione" we have a dialogue between Gregory and his deceased sister, Macrina; it treats of death, resurrection, and our last end. He defends human liberty against the fatalism of the astrologers in a work "On Fate", and in his treatise "On Children", dedicated to Hieros, Prefect of Cappadocia, he undertook to explain why Providence permits the premature death of children.

Ascetical Works
He wrote also on Christian life and conduct, e.g. "On the meaning of the Christian name or profession", addressed to Harmonius, and "On Perfection and what manner of man the Christian should be", dedicated to the monk Olympius. For the monks, he wrote a work on the Divine purpose in creation. His admirable book "On Virginity", written about 370, was composed to strengthen in all who read it the desire for a life of perfect virtue.

Sermons and Homilies
Gregory wrote also many sermons and homilies, some of which we have already mentioned; others of importance are his panegyric on St. Basil, and his sermons on the Divinity of the Son and of the Holy Ghost.