Macedonian phalanx in the context of "Kingdom of Macedon"

Philip II of Macedon (Ancient Greek: Φίλιππος, romanized: Phílippos; 382 BC – October 336 BC) was the king (basileus) of Macedon from 359 BC until his death in 336 BC. The rise of Macedon, from a kingdom initially at the periphery of classical Greek affairs, to a power that came to dominate Ancient Greece in the span of less than 25 years, was largely thanks to the character and policies of Philip. He was the father of Alexander the Great and a member of the ruling Argead dynasty that founded the kingdom of the Macedonians.

Philip achieved to dominate Greece during his reign by the reformation of the Macedonian army, including the establishment of the Macedonian phalanx, the use of combined arms tactics and his extensive use of siege engines and artillery, as well as by the use of effective diplomacy and marriage alliances. After defeating the Greek city-states of Athens and Thebes at the Battle of Chaeronea in 338 BC, Philip II led the effort to establish a federation of Greek states known as the Hellenic League, with him as the elected hegemon and commander-in-chief of Greece for a planned invasion of the Achaemenid Empire. However, his assassination by a royal bodyguard, Pausanias of Orestis, led to the immediate succession of his son Alexander, who would go on to invade the Achaemenid Empire in his father's stead.

Under the reign of Philip II (359–336 BC), the ancient kingdom of Macedonia, initially at the periphery of classical Greek affairs, came to dominate Ancient Greece in the span of less than 25 years, largely thanks to the character and policies of its king. In addition to utilising effective diplomacy and marriage alliances to achieve his political aims, Philip II was responsible for reforming the ancient Macedonian army into an effective fighting force. The Macedonian phalanx became the hallmark of the Macedonian army during his reign and the subsequent Hellenistic period. His army and engineers also made extensive use of siege engines. Chief among Philip's Thracian enemies was the ruler Kersebleptes, who may have coordinated a temporary alliance with Athens. In a series of campaigns stretching from 356 to 340 BC, Philip II managed to ultimately subjugate Kersebleptes as a tributary vassal, conquering much of Thrace in the process. Philip II also fought against the Illyrian king Bardylis, who threatened Macedonia proper, and against Grabos II and Pleuratus in Illyria (centred in modern-day Albania). In his newly conquered territories, he founded new cities such as Philippi, Philippopolis (modern Plovdiv, Bulgaria), Herakleia Sintike (Pirin Macedonia, Bulgaria), and Herakleia Lynkestis (modern Bitola, North Macedonia).

Philip II eventually campaigned against the city-state of Athens and her allies in the Aegean region, as well as Thebes after the decline of its hegemony in mainland Greece. In the defence of the Amphictyonic League of Delphi and in conjunction with the Thessalian League, Macedonia became a key player in the Third Sacred War (356–346 BC), defeating the Phocians, commanded by Onomarchus, at the Battle of Crocus Field in 352 BC. While poised to launch a direct assault on Athens in 346 BC, the Macedonian king was met with an Athenian embassy that arranged the Peace of Philocrates. As a result, Macedonia and Athens became allies, yet Athens was forced to relinquish its claims to the city of Amphipolis (in modern-day Central Macedonia).

The sarissa or sarisa was a long spear or pike about 5 to 7 meters (16 to 23 ft) in length. It was introduced by Philip II of Macedon and was used in his Macedonian phalanxes as a replacement for the earlier dory, which was considerably shorter. These longer spears improved the strength of the phalanx by extending the rows of overlapping weapons projecting towards the enemy. After the conquests of Alexander the Great, the sarissa was a mainstay during the Hellenistic era (4th–1st centuries BCE) by the Hellenistic armies of the diadochi Greek successor states of Alexander's empire, as well as some of their rivals.