A'thos (Gr. Hagion Oros, 'Holy Hill'), the most eastern of the three tongues of the Chalci-dice Peninsula on the Aegean Sea, connected with the mainland by a low and narrow isthmus, about a mile across. The length of the peninsula is about 31 miles; its breadth varies from 3 to 6 miles. At the southern extremity, a solitary peak rises abruptly to a height of 6346 feet above the sea. Xerxes cut a canal through the isthmus, traces of which still exist. This peninsula is the seat of twenty large monasteries, besides numerous hermitages and chapels. The entire number of monks is about 6000. They enjoy complete autonomy, subject to paying the Turkish government an annual tribute of about £3500. Caryes, the principal place in the peninsula, is picturesquely situated in the midst of vineyards and gardens, and has 1000 inhabitants. Here the market is held; but no female, even of the lower animals, is permitted on Athos. In the middle ages, Athos was the centre of Greek learning and Christian-Byzantine art. Now learning is at a very low ebb; scarcely more than two or three monks of tolerable education can be found in a monastery. The libraries are neglected, though containing several beautiful (but not important) manuscripts. See works by Curzon (1849; 6th ed. 1881), Athelstan Riley (1887), and Brockhaus (Leip. 1891).