. The monastery has two successive entrance gates. Passing through the great outer gate one reaches the outer courtyard. The places for the activities that needed to be carried out in a fortified space can be seen there. The outer gate was at the end of a vaulted gallery. The second gate leading to the main monastery building is called ‘gate of the wheel’. It was very heavy and not easily opened. It took its name from one wheel which was there to facilitate the monk who was responsible for opening and closing it.
The construction of the monastery in this fortified form has been associated with the Cretan-Venetian families of Kornaros and Mezzo in Sitia. Even to this day the southern wing is called the Kornaros wing and the northern one is called the Mezzo wing, names indicating the sponsors of the monastery.
The monastery was at its peak in the 14th and 15th centuries, judging by the large number of important Byzantine icons of that period, closely reflecting the evolution of Constantinople style in icon painting. This style was gradually introduced to Crete from the fall of Constantinople onwards.This period of prosperity continued undisturbed until 1612, when it was halted by a devastating earthquake that struck eastern Crete. During the Ottoman rule the monastery was frequently the subject of looting and slaughter by the Turks, but it managed to survive and help enslaved Greeks. Indeed, from 1856 onwards, a secret school was organized in the monastery complex, which taught literacy through religious texts under the auspices of the Dimogerontia (Community Elders’ Board). Candidate monks as well as the children of the people who lived in the area went to school there and learned to read and write.
The catholicon of the monastery, which is dedicated to the Nativity of the Virgin, was originally a small single-nave barrel-vaulted church. A second sizable vaulted space was later annexed on the West. The original chapel now serves as sanctuary. In the pointed arch of the extension, which is divided by a transverse reinforcing arch, high-quality frescoes dated to the second half of the 14th century survive in poor condition (Borboudakis 2004). All the scenes which have been recognized come from a wider Christological cycle of at least sixteen scenes. In a third construction phase, the single-nave barrel-vaulted church of St. John the Evangelist was erected, attached to the southern side of the catholicon. A very important collection of pictures, manuscripts, incunabula, prints, etchings and church relics is kept and exhibited in the monastery, making it an important cultural destination in eastern Crete.