The monastery was founded in 386 AD during the reign of the Emperor Theodosius I (375 - 395), Legend has it that two priests undertook its creation after discovering a miraculous icon of the Virgin Mary in a cave on the mountain.
During its long history, the monastery fell into ruin several times and was restored by various emperors. During the 6th century, it was restored and enlarged by General Belisarius at the behest of Justinian.
It reached its present form in the 13th century after gaining prominence during the reign of Alexios III (1349 - 1390) of the Komnenian Empire of Trebizond, established in 1204. At that time, the monastery was granted an amount annually from imperial funds. During the time of Manuel III, son of Alexius III, and during the reigns of subsequent princes, Sümela gained further wealth from imperial grants. Following the conquest by the Ottoman Sultan Mehmed II in 1461, it was granted the sultan's protection and given rights and privileges that were renewed by following sultans. The monastery remained a popular destination for monks and travelers through the years.
In 1682 and for a few decades, the monastery housed the Phrontisterion of Trapezous, a well-known Greek educational institution of the region.
The monastery was seized by the Russian Empire during the 1916-18 occupation of Trabzon.
The site was abandoned in 1923, following forced population exchanges between Greece and Turkey. The departing monks were not allowed to take any property with them, so they buried Sumela's famous icon under the floor of the monastery's St. Barbara chapel. In 1930, a monk secretly returned to Sumela and retrieved the icon, transferring it to the new Panagia Soumela Monastery, on the slopes of Mount Vermion, near the town of Naousa, in Macedonia, Greece.
Today the monastery's primary function is as a tourist attraction. It overlooks forests and streams, making it extremely popular for its aesthetic attraction as well as for its cultural and religious significance.
As of 2012, the Turkish government is funding restoration work, and the monastery is enjoying a revival in pilgrimage from Greece and Russia.
On 15 August 2010, Orthodox divine liturgy was again allowed after decades in the monastery compound.
A special pass issued by the Ecumenical Patriarchate of Constantinople is required to visit on Aug. 15, the day of the Assumption of Mary, when a big Christian Orthodox feast for the divine liturgy is held. Only 450 to 500 visitors are allowed in the monastery, although widescreen TVs are available to observe the divine liturgy at the cafe some hundred meters away from the monastery.(wikipedia)