Ancient Macedonian army in the context of "Battle of Crocus Field"

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.

Macedonia (/ˌmæsɪˈdoʊniə/ MASS-ih-DOH-nee-ə; Greek: Μακεδονία, Makedonía), also called Macedon (/ˈmæsɪdɒn/ MASS-ih-don), was an ancient kingdom on the periphery of Archaic and Classical Greece, which later became the dominant state of Hellenistic Greece. The kingdom was founded and initially ruled by the royal Argead dynasty, which was followed by the Antipatrid and Antigonid dynasties. Home to the ancient Macedonians, the earliest kingdom was centred on the northeastern part of the Greek peninsula, and bordered by Epirus to the southwest, Illyria to the northwest, Paeonia to the north, Thrace to the east and Thessaly to the south.

Before the 4th century BC, Macedonia was a small kingdom with its capital at Aigai, outside of the area dominated by the great city-states of Athens, Sparta and Thebes, and briefly subordinate to the Achaemenid Empire. During the reign of the Argead king Philip II (359–336 BC), Macedonia (with its capital at Pella) subdued mainland Greece and the Thracian Odrysian kingdom through conquest and diplomacy. With a reformed army containing phalanxes wielding the sarissa pike, Philip II defeated the old powers of Athens and Thebes in the Battle of Chaeronea in 338 BC. Philip II's son Alexander the Great, leading a federation of Greek states, accomplished his father's objective of commanding the whole of Greece when he destroyed Thebes after the city revolted. During Alexander's subsequent campaign of conquest, he overthrew the Achaemenid Empire and conquered territory that stretched as far as the Indus River. For a brief period, his Macedonian Empire was the most powerful in the world – the definitive Hellenistic state, inaugurating the transition to a new period of Ancient Greek civilization. Greek arts and literature flourished in the new conquered lands and advances in philosophy, engineering, and science spread across the empire and beyond. Of particular importance were the contributions of Aristotle, tutor to Alexander, whose writings became a keystone of Western philosophy.

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 Macedonians (Ancient Greek: Μακεδόνες, Makedónes) were an ancient tribe that lived on the alluvial plain around the rivers Haliacmon and lower Axios in the northeastern part of mainland Greece. Essentially an ancient Greek people, they gradually expanded from their homeland along the Haliacmon valley on the northern edge of the Greek world, absorbing or driving out neighbouring non-Greek tribes, primarily Thracian and Illyrian. They spoke Ancient Macedonian, which is usually classified by scholars as a dialect of Northwest Doric Greek, and occasionally as a distinct sister language of Greek or an Aeolic Greek dialect. However, the prestige language of Macedon during the Classical era was Attic Greek, replaced by Koine Greek during the Hellenistic era. Their religious beliefs mirrored those of other Greeks, following the main deities of the Greek pantheon, although the Macedonians continued Archaic burial practices that had ceased in other parts of Greece after the 6th century BC. Aside from the monarchy, the core of Macedonian society was its nobility. Similar to the aristocracy of neighboring Thessaly, their wealth was largely built on herding horses and cattle.

Although composed of various clans, the kingdom of Macedonia, established around the 7th century BC, is mostly associated with the Argead dynasty and the tribe named after it. The dynasty, also known as the Temenid dynasty, was allegedly founded by Perdiccas I, descendant of the legendary Temenus of Argos, while the region of Macedon derived its name from Makedon, a figure of Greek mythology. Traditionally ruled by independent families, the Macedonians seem to have accepted Argead rule by the time of Alexander I (r. 498 – 454 BC). Under Philip II (r. 359 – 336 BC), the Macedonians are credited with numerous military innovations, which enlarged their territory and increased their control over other areas extending into Thrace. This consolidation of territory allowed for the exploits of Alexander the Great (r. 336 – 323 BC), the conquest of the Achaemenid Empire, the establishment of the diadochi successor states, and the inauguration of the Hellenistic period in West Asia, Greece, and the broader Mediterranean world. The Macedonians were eventually conquered by the Roman Republic, which dismantled the Macedonian monarchy at the end of the Third Macedonian War (171–168 BC) and established the Roman province of Macedonia after the Fourth Macedonian War (150–148 BC).

Bardylis or Bardyllis (/bɑːrˈdɪlɪs/; Ancient Greek: Βάρδυλις; c. 448–358 BC) was an Illyrian king, and the founder of the first attested Illyrian dynasty. During his reign, Bardylis aimed to make Illyria a regional power interfering with Macedon. He united many southern Illyrian tribes under his realm and defeated the Macedonians and Molossians several times, expanding his dominion over upper Macedonia, including Lynkestis, and ruling over Macedon through a puppet king. Before the rise of Macedon, Illyrians were the dominant power in the region. Bardylis also led raids against Epirus, but his soldiers were eventually expelled from the region.

Most scholars hold that the Illyrian kingdom that was established by Bardylis was centered along Lake Ohrid and east to the Prespa Lakes, which was called Dassaretis later in Roman times, located on the border between Macedon and Epirus. Illyrians, in particular under Bardylis' leadership, held a remarkable role in the development of the Argead Macedonian military. Philip II and Alexander the Great spent at least some of their youth age at Illyrian courts, getting well familiar with Illyrian customs, habits and specially military strategies and techniques.