The Chalcidian League (Greek: Κοινόν τῶν Χαλκιδέων, Koinon tōn Chalkideōn, "League of the Chalcidians"), also referred to as the Olynthians[1] or the Chalcidians in Thrace (Χαλκιδεῖς ἐπί Θρᾴκης, Chalkideis epi Thrakēs)[2] to distinguish them from the Chalcidians in Euboea,[3] was a federal state that existed on the Chalcidice peninsula, on the shores of the northwest Aegean Sea, from around 430 BCE until it was destroyed by Philip II of Macedon in 348 BCE.