According to the Greek historian Theopompus of Chios, Europe had never seen a man like king Philip of Macedonia, and he called his history of the mid-fourth century BCE the Philippic History. Theopompus had a point. Not even his better known son Alexander has done so much to change the course of Greek history. Philip reorganized his kingdom, gave it access to the sea, expanded its power so that it could defeat the Achaemenid Empire, and subdued the Greek city-states, which never regained their independence again. To achieve this, he modernized the Macedonian economy, improved the army, and concluded several marital alliances. The result was a superpower with one weakness: it was as strong as its king. When Philip's son Alexander died, the institutions were too weak, and Macedonia never recovered.
When Philip was born in 382, Macedonia was not a very strong power. The historian Arrian of Nicomedia says that the Macedonians were "wandering about without resources, many of them clothed in sheepskins and pasturing small flocks in the mountains, defending them with difficulty against the Illyrians, Triballians and neighboring Thracians" (full text). This is exaggerated, but it is true that king Amyntas III, Philip's father, found it difficult to defend his country against its neighbors, and more or less had to lease his own kingdom from the Illyrians.
In 370, Amyntas died and was succeeded by Philip's elder brother Alexander II, who was forced to send his brother as a hostage to the Illyrians. Later, when Alexander had tried to expand his influence in Thessaly and had gotten involved in a war with Thebes, the only way to obtain peace was to send Philip as hostage to the house of the Theban politician Pammenes, a friend of the famous general Epaminondas. Philip was now at an age to understand what he saw, and learned a lot about warfare, about city life, and the importance of Persia, a Theban ally.
Meanwhile, king Alexander II had been assassinated by a man named Ptolemaeus of Aloros. His successor was a brother of Alexander II, Perdiccas III, who was one year older than Philip, but still too young to be a ruler. Ptolemaeus was his regent. In 365, when Perdiccas was old enough, he became king, and immediately killed Ptolemaeus. His younger brother returned to Macedonia, which was still a weak kingdom.
Yet, the seeds of change had been sown. Alexander had reorganized the Macedonian phalanx (to be discussed below), Philip arrived with new military and political knowledge, and Perdiccas knew how to play the diplomatic game. He was forced by the Athenians to cooperate with them in an attempt to conquer the city of Amphipolis, and indeed, Perdiccas did fight together with the Athenian commander Timotheus, but once Amphipolis had been captured, he kept it for himself and broke off the collaboration.
Amphipolis was important. It controlled the river Strymon, which passed along strategically important forests with high trees, necessary for anyone who wanted to build a ship. The city also controlled the road from Macedonia to Thrace. And, the most important thing: there were gold mines. As long as Macedonia had Amphipolis, it had the resources to build up an army and it could blackmail any sea power. Immediately, Perdiccas invited the Athenian Callistratus to reform the Macedonian economy and toll system. However, the king was not to see the edifice for which he had laid the foundations, because in the last weeks of 360, his army was defeated by the Illyrian king Bardylis. Perdiccas and 4,000 others died in action.
He left a very young son, Amyntas, and Philip became regent. Immediately, Athens opened secret negotiations and offered to support him when he established his throne, and asked him to give up Amphipolis. Philip replied to this overture by removing the garrison from Amphipolis, which was now independent again. At the same time, he paid the Thracians and Paeones, which gave him the rest he needed. This temporizing diplomacy paid off. In 359, he recruited and trained a new army, and in the spring of 358 he was ready to strike. The Paeones were subdued and would never be independent again. In the summer, Bardylis had to face the new Macedonian army, and saw how his own men were massacred. The mines of Damastion were from now on Macedonian.
Shortly before Philip set out to the Paeones, king Artaxerxes II Mnemon of Persia died and was succeeded by his son Artaxerxes III Ochus, an energetic man whose main aim was to reconquer Egypt. To achieve this, he needed to control the sea, and he therefore had to take action against Athens, which had a navy and had supported Egypt on more than one occasion. The satrap of Caria, Maussolus, was able to provoke a revolt among the Athenian allies. This was the beginning of the Social War (357-355).
Immediately, Philip (who had probably accepted money from the king of Persia but needed no encouragement anyhow) captured Amphipolis. The inhabitants were treated kindly, although the Macedonian ruler ordered several people to be exiled and placed a garrison in the city. He now promised to give up his new conquest if the Athenians would give him Pydna, an important port. The Athenians listened to the offer, but when Philip understood that they were not capable of fighting two wars at the same time, he decided to keep both cities. From now on, everyone in Greece understood that for the first time in history, the Macedonians were united, possessed money and an army, and were led by a capable leader.
In the same year 357, Philip married to Olympias, the daughter of the king of the Molossians, a nation living between the Greeks, Macedonians, and Illyrians. He also married a Macedonian princess named Phila of Elymiotis (a district in the west) and Audata of Illyria. The three marriages secured Macedonia's western border. When the winter came, Olympias was pregnant, and Philip, now king for three years, could already look back upon a very successful reign. The Thracian frontier was safe now that he had conquered Amphipolis; in the north, the Paeones had been subdued; in the northwest, the Illyrians were decisively defeated; in the west, the Molossians were his allies; he had obtained mines and had given Macedonia its first access to the sea, Pydna. But this was only the beginning.