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a war on the island of Euboea between the cities of Chalcis and Eretria over control of the fertile Lelantine plain (Lelanton pedion) in the seventh century B.C. In this war, Samos, Corinth, and the cities of the Thracian coast sided with Chalcis, and Miletus and Megara with Eretria. The Lelantine War thus became a war between two alliances of commercial cities of ancient Greece. The war ended in a victory of Chalcis and its allies; the Thessalian cavalry played the decisive role in the victory.