Mount Athos is a mountain and a peninsula in Macedonia, northern Greece, called Άγιο Όρος (''Ayio Oros'' or "Holy Mountain") in Modern Greek, or Ἅγιον Ὄρος (''Hagion Oros'') in Classical Greek languageGreek. It is home to 20 Eastern Orthodox monasterymonasteries and forms an autonomous state under Greek sovereignty. Only monasticismmonks are allowed to live on Athos and the current population numbers around 1,400. The peninsula, the easternmost "leg" of the larger Chalkidiki peninsula, protrudes into the Aegean Sea for some 60 km at a width between 7 to 12 km and covers an area of about 390 square kilometrekm², with the actual Mount Athos and its steep, densely forested slopes reaching up to 2,033 m.
Mount Athos as a monastic community was formally founded in 963, when the monk Athanasios established the monastery of Great Lavra, still the largest and most prominent of the 20 monasteries. It enjoyed the protection of the emperors of the Byzantine Empire during the following centuries and its wealth and possessions grew considerably. The Fourth Crusade in the 13th century brought new Roman Catholic overlords which forced the monks to seek protection from Pope Innocent III, until the restoration of the Byzantine Empire. It was raided by CataloniaCatalan mercenaries in the 14th century, a century that also saw the theological conflict over the hesychasm practised on Mount Athos and defended by Gregory Palamas.