History of the Peloponnesian War

And Perdiccas induced the Chalcidians to abandon and demolish their towns on the seaboard, and settling inland at Olynthus, to make that one city a strong place: meanwhile to those who followed his advice he gave a part of his territory in Mygdonia round Lake Bolbe as a place of abode while the war against the Athenians should last. They accordingly demolished their towns, removed inland, and prepared for war.

The thirty ships of the Athenians, arriving before the Thracian places, found Potidaea and the rest in revolt.

Their commanders considering it to be quite impossible with their present force to carry on war with Perdiccas, and with the confederate towns as well, turned to Macedonia, their original destination, and having established themselves there, carried on war in co-operation with Philip, and the brothers of Derdas, who had invaded the country from the interior.

Meanwhile the Corinthians, with Potidaea in revolt, and the Athenian ships on the coast of Macedonia, alarmed for the safety of the place, and thinking its danger theirs, sent volunteers from Corinth, and mercenaries from the rest of Peloponnese, to the number of sixteen hundred heavy infantry in all, and four hundred light troops.