The Holy Monastery of Megisti Lavra is the largest and the first in the hierarchy Monastery of Mount Athos. It is located at the southeastern tip of the Athos peninsula, at an altitude of 40 meters, on a rocky surface and was built in 963 by Saint Athanasios the Athonite, with money offered by the emperors Nikiforos Fokas and Ioannis Tsimiskis. It maintains the first place among the other Monasteries of Mount Athos due to the wealth and relics it has in its possession (manuscripts, historical documents, gold bullions, portable icons and more).
The Katholikon of the Monastery is the first to be built on Mount Athos, at the end of the 10th century, being a model of Mount Athos temples. It is roofed with a large dome, which symbolizes the heavens, supported by four columns. The central part is decorated with frescoes by the Cretan hagiographer Theophanes, the oldest of which dates to 1535. The walls and ceiling of the narthex and the exonarthex were painted in 1854. The katholikon includes two large chapels, where the Saints Saranda the Martyrs are located ( tomb of Saint Athanasios) and Agios Nikolaos while the altar has hagiographies dating from 1512.
The relics of the Monastery include, among others, relics as well as the stick of Agios Athanasios, the sack and the crown of the emperor Nikiforos Fokas, various valuable icons, gospels, relics of many Saints. The library keeps 2,200 codes (470 parchments), 50 membrane scrolls and 10,000 leaflets. Initially it was honored on the feast of the Annunciation of the Virgin, but today it is honored in the memory of Saint Athanasios of Athonitis, on July 5.