The Monastery of St. Paul ( Greek: Μονή Αγίου Παύλου ) is a monastery on Mount Athos , the 14th most important mountain on Mount Athos . It is located on the western side of the Athos Peninsula. It was founded in the 10th century by St. Paul Xyropotamian, son of Emperor Michael I Rangaba . When the monastery was damaged, only ruins remained. Those ruins were bought from the Xyropotam monastery by two Serbian lords from Kostur . They were the great chemist Gerasim Radonja and Antonija Bagash, who also became a monk later. With the help of brothers Vuk and Grgur Branković, they thoroughly renovated the monastery of St. Paul. According to one version of the event, the buried body of Vuk Branković was transferred to the Holy Mountain by the great chemist Gerasim , and stored in his endowment - that monastery. The monastery is square in shape surrounded by high and strong rocks. The cathedral monastery church is dedicated to the Assumption of the Lord . In the monastery treasury are kept the particles of the Life-giving Cross, parts of the relics of St. Gregory the Theologian , Maximus the Confessor , Venerable Kalinik , Basil the Great , Patriarch Theodore of Alexandria and many others. About 30 monks now live in the monastery . The monastery library contains 494 manuscripts and 12,000 printed books. The monastery has been built since 1988 . year, together with the other nineteen monasteries on Mount Athos, is on the UNESCO World Heritage List as part of the monuments of the Middle Ages united under the protected whole Mount Athos. This holy family has been Serbian for centuries, as Antonio Vučetić writes .