Atuos (mod. Gr. Hagion Oras, holy mountain; Turk. Aineros), the easternmost of the three peninsulas projecting from ancient Chal-cidice, in the N. W. part of the AEgean sea, now included in the Turkish eyalet of Salonica, about 30 m. long and from 4 to 7 broad. It is mountainous, and cut by numerous ravines. At its extremity stands the mountain from which it takes its name. Mt. Athos is about 6,350 ft. high, with a peak of white limestone, while its lower rocks are of gneiss and argillaceous slate. The sides of the mountain are flanked with vast forests of pines, oaks, and chestnuts, the pines growing to an immense size. Various kinds of aromatic herbs grow here in abundance, out of which the monks extract the oils and essence and use them for medicinal purposes, perfumery, and ingredients in incense. It was across the isthmus which connects the peninsula of Athos with the mainland that Xerxes cut a canal for his ships, in his invasion of Greece. The remains of this canal, according to the best authorities, are still distinctly visible through most of its extent. Near the middle of its course it is not discernible, having been filled up. Athos was so called from the giant of that name who in the Grecian mythology hurled the mountain at the gods.
The peninsula in ancient times contained several flourishing cities and a temple of Jupiter; and in the middle ages it was dotted over with hermitages and monasteries, 20 of which still remain. Most of these monasteries were founded by Byzantine princes. It was here that ambitious malcontents of the court of Constantinople, favorites in disgrace, and even private individuals, retired to await a change of affairs or return to favor. The monks at present number about 6,000, from Greece, Bulgaria, Roumania, and Russia, in all of which countries the convents of Athos possess estates. No female is permitted to enter the peninsula. The monks are ruled by an administrative assembly (protaton), composed of delegates from the various convents chosen for a term of four years. The administration of justice and the management of the revenue are also vested in this body. The assembly has its seat at Karias, the capital of the peninsula. A Turkish aga resides in Athos and collects an annual tribute from the convents. In the middle ages these convents were the seat of Greek science and the centre of Byzantine Christian knowledge, and possessed many large libraries.