TR1397 - Sümela Monastery (The Monastery of Virgin Mary) (2000)

"Sumela is a monastic complex built into the rock cliffs of the Altmdere Valley. It is construction began in 385 AD; and continued until the 19 th century. Barnabas, a monk from Athens and his nephew Sophronios built the section which comprised the first two rooms of the monastry in rocks. The Byzantine Emperor Justinian (AD 527-568) ordered the enlagement of the monastery. The monastery was looted and burnt by the Byzantines in AD 650. However the Comnenids restored and enlarged the monastey. The monastery with its 72 rooms and a rich library, lived its most flourishing time during the period of Alexios III 8 Michael I."

Courtesy of onur from postcrossing forum