Saint Niphon II, the Patriarch of Constantinople, was from the Peloponnese, Greece. His parents were named Manuel and Maria, and he was named Nicholas in Holy Baptism. Later, he was tonsured as a monk at Epidaurus, receiving the new name Niphon.
After the death of his Elder Anthony, he went to Mount Athos, where he occupied himself by copying books. Afterward, he was chosen as Metropolitan of Thessaloniki. In 1486 he occupied the Patriarchal throne of Constantinople.
Banished in 1488, the Saint went to the Holy Mountain, at first to Vatopedi Monastery, Athos, Greece, and then to the monastery of Saint John the Forerunner (Dionysiou). He concealed his rank and occupied the lowliest position. By God’s providence, his rank was revealed to the brethren of the monastery. Once, when the Saint was returning from the forest where he had gone for firewood, all the brethren went out to meet him, greeting him as Patriarch. But even after this, the Saint continued to share various tasks with the brethren. In all, he served three times as Patriarch of Constantinople: 1486-1488; 1497-1498; and 1502.
Saint Niphon reposed on September 3, 1508 at the age of 90. Immediately after his death, he was honored as a Saint in many places. On August 16, 1517, in the newly-established monastery of Curtea de Argeş, Patriarch Theoleptos of Constantinople, together with the Synod of the Romanian Lands, and the Igoumens of the Athonite monasteries, performed the solemn glorification of Saint Niphon, decreeing that his Feast Day be celebrated on August 11th.
His relics are kept in a shrine at the Monastery of Dionysiou, Athos, where there is also a chapel dedicated to him. In gratitude, the Athonite monks gave the Saint’s head and hand to Nyagoe Basarab, who placed them in the Monastery he built at Curtea de Argeş in what is now Romania. In the 18th century, these relics were placed in a silver reliquary.
At the behest of the Holy Synod of the Romanian Orthodox Church, they were brought to Craiova, to the church of Saint Dēmḗtrios, the Metropolitan cathedral of Oltenia on October 25, 1949.
In 2009, the relics of Saint Niphon were moved to the Cathedral of the Ascension of the Lord at Târgovişte
Apolytikion
The truth of things hath revealed thee to thy flock as a rule of faith, an icon of meekness, and a teacher of temperance; for this cause, thou hast achieved the heights by humility, riches by poverty. O Father and Hierarch Niphon, intercede with Christ God that our souls be saved. Through the prayers of our Holy Fathers, Lord Jesus Christ our God, have mercy on us and save us! Amen!
Source:
https://stgeorge.org/2021/08/st-niphon-patriarch-of-constantinople/