Thasos (now Thasso), the most northerly island of the Grecian archipelago, belonging to Turkey, lying off the S. coast of Roumelia (vilayet of Salonica), nearly circular in form; area, about 85 sq. m pop. about 6,000, mostly Greeks. The centre of the island is occupied by Mt. Ipsario, a summit about 3,500 ft. above the sea, and thickly covered with fir trees. The principal ancient town, bearing the same name, was upon three eminences near the N. coast, and some remains of it still exist. The soil is not fertile, and the inhabitants, scattered in about a dozen small villages, do not produce grain enough for their own consumption. The vine was formerly cultivated, and the wine of Thasos was celebrated, but little or none is now produced. In ancient times it contained also valuable gold mines, opened by the Phoenicians, and marble quarries. - Thasos was once of great importance. It was said to have been settled by the Phoenicians, led by Thasos, the son of Agenor, when in search of Europa. Toward the close of the 8th century B. C. it was colonized by settlers from Paros, who very soon became powerful, and obtained considerable possessions also on the coast of Thrace. The gold mines worked by the islanders were very productive, leaving them a clear surplus revenue of about $300,000 annually.

They were subdued by the Persians, and afterward became dependent on the maritime empire of Athens; but in 465, in consequence of disputes, the Athenians subjugated and despoiled the island, after a siege of more than two years. Its subsequent history is one of almost constant conflict with Athens, to which it was nominally subject, until the time of the Roman wars, when it submitted to Philip V. of Macedon; but after the battle of Cynoscephalae (197) it became a free state.