St. Gregory Palamas, Archbishop of Thessalonica, was born in 1296 in Asia Minor. During the Turkish invasion, the family fled to Constantinople and found shelter at the court of Andronikos II Palaiologos (1282-1328). St. Gregory's father became a major dignitary under the emperor, but died soon after, and Andronikos himself took part in the upbringing and education of the orphaned boy. Possessing excellent abilities and great diligence, Gregory easily mastered all the subjects that made up the full course of medieval higher education. 
The emperor wanted the young man to devote himself to government activities, but Gregory, barely reaching the age of 20, retired to the Holy Mount Athos in 1316 (according to other sources, in 1318) and entered the monastery of Vatopedi as a novice, where, under the guidance of the elder, St. Nicodemus of Vatopedi (July 11), he took vows and began the path asceticism. A year later, the holy Evangelist John the Theologian appeared to him in a vision and promised his spiritual protection. Gregory's mother, along with his sisters, also became a monk.
After the repose of Elder Nicodemus, Monk Gregory performed his prayer feat for 8 years under the guidance of Elder Nicephorus the Hesychast, and after the latter's death he moved to the Monastery of St. Athanasius. Here he served meals, and then became a church singer. But three years later (1321), striving for higher levels of spiritual perfection, he settled in a small hermit monastery in Glossia. The abbot of this monastery began to teach the young man concentrated spiritual prayer, a clever practice that was gradually developed and assimilated by monks, starting with the great hermits of the IV century Evagrius of Pontus and St. Macarius of Egypt (January 19). After the external prayer methods of intelligent work were given detailed coverage in the works of Symeon the New Theologian (March 12) in the 11th century, it was adopted by Athos ascetics. The experimental application of intelligent doing, which requires solitude and silence, is called hesychasm (from Greek. peace, silence), and his practitioners themselves became known as hesychasts. During his stay in Glossia, the future saint was fully imbued with the spirit of hesychasm and accepted it for himself as the basis of life. In 1326, due to the threat of a Turkish attack, he and his brethren moved to Thessalonica, where he was ordained a priest at the same time.
Saint Gregory combined his duties as a presbyter with the life of a hermit: he spent five days of the week in silence and prayer, and only on Saturday and Sunday did the pastor go out to the people to perform divine services and deliver sermons. His teachings often caused those who came to the temple to be moved and shed tears. However, complete detachment from public life was unusual for the saint. Sometimes he attended theological meetings of the city's educated youth, led by the future Patriarch Isidore. Returning from Constantinople one day, he discovered a place near Thessalonica called Berea, which was convenient for a secluded life. Soon he gathered a small community of hermit monks here and led it for 5 years. In 1331, the saint retired to Mount Athos and retired to the hermitage of St. Sava, near the Monastery of St. Athanasius. In 1333, he was appointed abbot of the Esfigmen Monastery in the northern part of the Holy Mountain. In 1336, the saint returned to the monastery of Saint Sava, where he began his theological studies, which he continued to do until the end of his life.
Meanwhile, in the 30s of the 14th century, events were brewing in the life of the Eastern Church, which placed St. Gregory among the most significant ecumenical apologists of Orthodoxy and brought him fame as a teacher of hesychasm.
Around 1330, the learned monk Varlaam came to Constantinople from Calabria. The author of treatises on logic and astronomy, a skilled and witty speaker, he received a chair at the metropolitan University and began to interpret the writings of Dionysius the Areopagite (October 3), whose apophatic theology was recognized equally by both the Eastern and Western Churches. Soon Barlaam went to Mount Athos, got acquainted there with the way of the spiritual life of the hesychasts and, on the basis of the dogma of the incomprehensibility of the being of God, declared clever doing a heretical error. Traveling from Mount Athos to Solun, from there to Constantinople, and then back to Solun, Barlaam engaged in arguments with the monks and tried to prove the creation of the Tabor light; at the same time, he did not hesitate to ridicule the monks' stories about prayer receptions and spiritual insights.
Saint Gregory, at the request of the Athos monks, first addressed them with oral exhortations. But seeing the failure of such attempts, he put his theological arguments in writing. This is how the "Triads in Defense of the Holy Hesychasts" appeared (1338). By 1340, the Athonite ascetics, with the participation of the saint, had compiled a common response to Barlaam's attacks – the so-called "Svyatogorsky Tomos". At the Council of Constantinople in 1341, a dispute between St. Gregory Palamas and Barlaam took place in St. Sophia's Church, focusing on the nature of the Tabor light. On May 27, 1341, the Council adopted the position of St. Gregory Palamas that God, inaccessible in His Essence, manifests Himself in energies that are directed to the world and accessible to perception, like the light of Tabor, but are not sensual and uncreated. Barlaam's teaching was condemned as heresy, and he himself, anathematized, retired to Calabria.
But the disputes between the Palamites and the Barlaamites were far from over. The latter included Varlaam's disciple, the Bulgarian monk Akindin, and Patriarch John XIV Kaleka (1341-1347); Andronikos III Palaiologos (1328-1341) was inclined towards them. Akindin issued a number of treatises in which he declared St. Gregory and the Athos monks to be the culprits of the church troubles. The saint wrote a detailed refutation of Akindin's conjectures. Then the patriarch excommunicated the saint from the Church (1344) and subjected him to a prison sentence that lasted three years. In 1347, when John XIV was succeeded on the patriarchal throne by Isidore (1347-1349), St. Gregory Palamas was released and elevated to the rank of Archbishop of Thessalonica. In 1351, the Blachernae Cathedral solemnly testified to the Orthodoxy of his teaching. But the people of Thessalonica did not accept St. Gregory immediately: he had to live in different places. On one of his trips to Constantinople, a Byzantine galley fell into the hands of the Turks. Saint Gregory was sold as a prisoner in various cities for a year, but even then he tirelessly continued to preach the Christian faith.
Only three years before his death, he returned to Solun. On the eve of his repose, St. John Chrysostom appeared to him in a vision. With the words "To the mountain! St. Gregory Palamas peacefully reposed to God on November 14, 1357. In 1368, he was canonized at the Council of Constantinople under Patriarch Philotheos (1354-1355, 1362-1376), who wrote the life and service of the saint.