Aya Yorgi Greek Monastery / Yücetepe
On the highest hill of Büyükada, the largest and perhaps the most beautiful of the Istanbul islands, is the Agios Georgios Greek Orthodox Monastery, popularly known as Aya Yorgi. This monastery takes its name from A.D. It is named after St. Georgios, an Anatolian (Cappadocian) officer in the Roman army, who was martyred by pagans for his Christian faith in the 3rd century and whose tomb is in Palestine today. According to existing rumors, the monastery has a history of more than a thousand years and dates back to A.D. It was built in 963 during the reign of Byzantine Emperor Nikephoros Phocas.
The miraculous icon of St. George was given as a gift by the Women's Monastery of Empress Irene in Büyükada. In the gold-sealed decree of the Byzantine Emperor Manuel Komninos dated 1158, Istanbul Islands and the monasteries there are mentioned, and the name Kodono is also mentioned among them. According to the 19th century historian Manuel Gedeon, this name is none other than the Aya Yorgi Kudunas (Çıngırakçı) Monastery in Büyükada.
Source Türkiye Culture Portal History of Istanbul