Deprived of all hope of aid from Athens, the Amphipolitans still held out as long as they could. But a party in the town entered into correspondence with Philip to betray it, and the defence thus gradually became feebler. At length he made a breach in the walls, sufficient, with the aid of partisans within, to carry the city by assault, not without a brave resistance from those who still remained faithful. All the citizens unfriendly to him were expelled or fled, the rest were treated with lenity; but we are told that little favor was shown by Philip towards those who had helped in the betrayal.[489]

Amphipolis was to Philip an acquisition of unspeakable importance, not less for defence than for offence. It was not only the most convenient maritime station in Thrace, but it also threw open to him all the country east of the Strymon, and especially the gold region near Mount Pangæus. He established himself firmly in his new position, which continued from henceforward one of the bulwarks of Macedonia, until the conquest of that kingdom by the Romans. He took no steps to fulfil his promise of handing over the place to the Athenians, who doubtless sent embassies to demand it. The Social War, indeed, which just now broke out, absorbed all their care and all their forces, so that they were unable, amidst their disastrous reverses at Chios and elsewhere, to take energetic measures in reference to Philip and Amphipolis. Nevertheless he still did not peremptorily refuse the surrender, but continued to amuse the Athenians with delusive hopes, suggested through his partisans, paid or voluntary, in the public assembly.

It was the more necessary for him to postpone any open breach with Athens, because the Olynthians had conceived serious alarm from his conquest of Amphipolis, and had sent to negotiate a treaty of amity and alliance with the Athenians. Such an alliance, had it been concluded, would have impeded the farther schemes of Philip. But his partisans at Athens procured the dismissal of the Olynthian envoys, by renewed assurances that the Macedonian prince was still the friend of Athens, and still disposed to cede Amphipolis as her legitimate possession. They represented, however, that he had good ground for complaining that Athens continued to retain Pydna, an ancient Macedonian seaport.[490] Accordingly they proposed to open negotiations with him for the exchange of Pydna against Amphipolis. But as the Pydnæans were known to be adverse to the transfer, secrecy was indispensable in the preliminary proceedings, so that Antiphon and Charidemus, the two envoys named, took their instructions from the Senate and made their reports only to the Senate. The public assembly being informed that negotiations, unavoidably secret, were proceeding, to ensure the acquisition of Amphipolis—was persuaded to repel the advances of Olynthus, as well as to look upon Philip still as a friend.[491]

The proffered alliance of the Olynthians was thus rejected, as the entreaty of the Amphipolitans for aid had previously been. Athens had good reason to repent of both. The secret negotiation brought her no nearer to the possession of Amphipolis. It ended in nothing, or in worse than nothing, as it amused her with delusive expectations, while Philip opened a treaty with the Olynthians, irritated, of course, by their recent repulse at Athens. As yet he had maintained pacific relations with the Athenians, even while holding Amphipolis contrary to his engagement. But he now altered his policy, and contracted alliance with the Olynthians; whose friendship he purchased not only by ceding to them the district of Anthemus (lying between Olynthus and Therma, and disputed by the Olynthians with former Macedonian kings), but also by conquering and handing over to them the important Athenian possession of Potidæa.[492] We know no particulars of these important transactions. Our scanty authorities merely inform us, that during the first two years (358-356 B. C.), while Athens was absorbed by her disastrous Social War, Philip began to act as her avowed enemy. He conquered from her not only Pydna and other places for himself, but also Potidæa for the Olynthians. We are told that Pydna was betrayed to Philip by a party of traitors in the town;[493] and he probably availed himself of the secret propositions made by Athens respecting the exchange of Pydna for Amphipolis, to exasperate the Pydnæans against her bad faith; since they would have good ground for resenting the project of transferring them underhand, contrary to their own inclination. Pydna was the first place besieged and captured. Several of its inhabitants, on the ground of prior offence towards Macedonia,[494] are said to have been slain, while even those who had betrayed the town were contemptuously treated. The siege lasted long enough to transmit news to Athens, and to receive aid, had the Athenians acted with proper celerity in despatching forces. But either the pressure of the Social War—or the impatience of personal service as well as of pecuniary payment—or both causes operating together—made them behindhand with the exigency. Several Athenian citizens were taken in Pydna and sold into slavery, some being ransomed by Demosthenes out of his own funds; yet we cannot make out clearly that any relief at all was sent from Athens.[495] If any was sent, it came too late.

Equal tardiness was shown in the relief sent to Potidæa[496]—though the siege, carried on jointly by Philip and the Olynthians, was both long and costly[497]—and though there were a body of Athenian settlers (Kleruchs) resident there, whom the capture of the place expelled from their houses and properties.[498] Even for the rescue of these fellow-citizens, it does not appear that any native Athenians would undertake the burden of personal service; the relieving force despatched seems to have consisted of a general with mercenary foreigners; who, as no pay was provided for them, postponed the enterprise on which they were sent to the temptation of plundering elsewhere for their own profit.[499] It was thus that Philip, without any express declaration of war, commenced a series of hostile measures against Athens, and deprived her of several valuable maritime possessions on the coast of Macedonia and Thrace, besides his breach of faith respecting the cession of Amphipolis.[500] After her losses from the Social War, and her disappointment about Amphipolis, she was yet farther mortified by seeing Pydna pass into his hands, and Potidæa (the most important possession in Thrace next to Amphipolis) into those of Olynthus. Her impoverished settlers returned home, doubtless with bitter complaint against the aggression, but also with just vexation against the tardiness of their countrymen in sending relief.

These two years had been so employed by Philip as to advance prodigiously his power and ascendency. He had deprived Athens of her hold upon the Thermaic gulf, in which she now seems only to have retained the town of Methônê, instead of the series of ports round the gulf acquired for her by Timotheus.[501] He had conciliated the good-will of the Olynthians by his cession of Anthemus and Potidæa; the latter place, from its commanding situation on the isthmus of Pallenê, giving them the mastery of that peninsula,[502] and ensuring (what to Philip was of great importance) their enmity with Athens. He not only improved the maritime conveniences of Amphipolis, but also extended his acquisitions into the auriferous regions of Mount Pangæus eastward of the Strymon. He possessed himself of that productive country immediately facing the island of Thasos; where both Thasians and Athenians had once contended for the rights of mining, and from whence, apparently, both had extracted valuable produce. In the interior of this region he founded a new city called Philippi, enlarged from a previous town called Krenides, recently founded by the Thasians; and he took such effective measures for increasing the metallic works in the neighborhood, that they presently yielded to him a large revenue; according to Diodorus, not less than one thousand talents per annum.[503] He caused a new gold coin to be struck, bearing a name derived from his own. The fresh source of wealth thus opened was of the greatest moment to him, as furnishing means to meet the constantly increasing expense of his military force. He had full employment to keep his soldiers in training: for the nations of the interior—Illyrians, Pæonians, and Thracians—humbled but not subdued, rose again in arms, and tried again jointly to reclaim their independence. The army of Philip—under his general Parmenio, of whom we now hear for the first time—defeated them, and again reduced them to submission.[504]

It was during this interval too that Philip married Olympias, daughter of Neoptolemus prince of the Molossi,[505] and descended from the ancient Molossian kings, who boasted of an heroic Æakid genealogy. Philip had seen her at the religious mysteries in the island of Samothrace, where both were initiated at the same time. In violence of temper—in jealous, cruel, and vindictive disposition—she forms almost a parallel to the Persian queens Amestris and Parysatis. The Epirotic women, as well as the Thracian, were much given to the Bacchanalian religious rites, celebrated with fierce ecstasy amid the mountain solitudes in honor of Dionysius.[506] To this species of religious excitement Olympias was peculiarly susceptible. She is said to have been fond of tame snakes playing around her, and to have indulged in ceremonies of magic and incantation.[507] Her temper and character became, after no long time, repulsive and even alarming to Philip. But in the year 356 B. C. she bore to him a son, afterwards renowned as Alexander the Great. It was in the summer of this year, not long after the taking of Potidæa, that Philip received nearly at the same time, three messages with good news—the birth of his son; the defeat of the Illyrians by Parmenio; and the success of one of his running horses at the Olympic games.[508]