supreme. Macedom was thus in effect the principal land power to the north of the Peloponnese; and her king had both displayed military genius, and had shown that he was in command of an army with which it was already a question whether any single Greek state could cope. The battle just fought was on a very considerable scale, and could not have failed to suggest unpleasant apprehensions to the mind of every thinking politician. Philip might very possibly follow up his success with an instant invasion of northern Greece. He did in fact advance on Thermopylæ; but Athens had forestalled him, and the famous pass was guarded by a force before which he thought it prudent to retire. The Athenians exulted in the reflection that they had once again been the deliverers of Greece. But their joy was doomed to be of very brief duration.
For a few months the king of Macedon employed himself in securing a firm hold on Thessaly. Meanwhile his cruisers and privateers, of which he had contrived to raise a formidable number, infested the northern islands and coasts of the Ægean, to the great annoyance and injury of Athenian trade. In the autumn of 352 B.C. he hurried northwards, entered Thrace, and took advantage of its intestine feuds, with a view to getting the country under his control. In November news reached Athens, the serious import of which could not be misunderstood. Philip was besieging Heræum—a place probably on the northern coast of the Propontis, to the west of Perinthus. It was contiguous to the Thracian Chersonese; occupied,
