or Oreus, in Ancient Geography, an important city of Euboea, on the northern extremity of the island, and giving name to the district of Histioeotis. It was a very ancient city, and like most of the old cities of Greece, its origin is doubtful and obscure. When the Persians were finally expelled from Greece, it passed into the hands of the Athenians, and when Euboea revolted from that people, and was again subdued, the old inhabitants of the town were expelled, and 2000 Athenian colonists settled in their stead. It was at this date that the city exchanged its original name for that of Oreus, by which it was afterwards more generally known. At the end of the Peloponnesian War the descendants of the old inhabitants were restored by the Spartans, under whose dominion the city had fallen, and to whom it remained faithful till the battle of Leuctra, when it revolted from them. In the war between Philip and the Greeks Oreus was frequently contested, and in B.C. 200 it was stormed by the Romans. Under the Romans Oreus gradually fell into decay. Some ruins of its fortifications are all that now remain to tell of its ancient greatness.