The Third Macedonian War (171–168 BC) was a war fought between the Roman Republic and King Perseus of Macedon. In 179 BC, King Philip V of Macedon died and was succeeded by his ambitious son Perseus. He was anti-Roman and stirred anti-Roman feelings around Macedonia. In 172 BC, a Roman commission visited Perseus and required of him concessions which meant the extinction of his independence. Upon his refusal to comply with the demands they returned home and Rome declared war.

Most of the war was fought in Macedon as well as neighbouring Thessaly, where the Roman troops were stationed. After an inconclusive battle at Callinicus in 171 BC, and several years of campaigning, Rome decisively defeated the Macedonian forces at the Battle of Pydna in 168 BC, ending the war.

Rome's victory ended the Antigonid dynasty and brought an effective end to the independence of the Hellenistic kingdom of Macedon, although formal annexation was some years away. The kingdom was divided into four client republics, called , with capitals located at Amphipolis, Thessalonica, Pella, and Pelagonia,; ; . which were members of a federal league, the League of the Macedonians. Roman prestige and authority in Greece greatly increased.

Background

In 179 BC, King Philip V of Macedon died and his ambitious son, Perseus, ascended the throne. In pursuit of an alliance, Perseus married Laodice, the daughter of Seleucus IV the king of the Seleucid Empire. Perseus' daughter was set to marry Prusias II of Bithynia (in north-western Anatolia, modern Turkey), who was an enemy of Eumenes II of Pergamon (in western Anatolia), an ally of Rome.

Amid these alliances, Abrupolis, the king of the Thracian tribe of the Sapaeans and an ally of the Romans attacked Macedon, laid it waste as far as Amphipolis, and overran the gold mines of Mount Pangaeus. He was repulsed and then driven out of his territories by Perseus. This conflict contributed to the tensions that led to war, because Rome took issue with the ousting of its ally.

Perseus made an alliance with Cotys IV, the king of the Odrysian kingdom, the largest state in Thrace. He enlarged his army. He also announced that he could carry out reforms in Greece and restore its previous strength and prosperity. Perseus sent agents to seek support in the Greek states and cities. He gained the support of Greeks who were treated generously, saw Perseus as their kindred, were keen on revolutionary change, or did not want to be at Rome's mercy.Livy, The History of Rome, 42.5.5–6. Perseus' propaganda and political manoeuvres around Greece created bitter disputes between pro-Roman and pro-Perseus factions.

At the beginning of 173 BC, the Romans sent commissioners to Aetolia and Macedonia, but they were not given the opportunity to meet Perseus. The Romans surmised that he was preparing for war. Aetolian cities experienced increasingly violent internal conflicts. A Roman envoy attended the session of the Aetolian council at Delphi. He asked both factions to abstain from war. This was agreed through an exchange of hostages, who were sent to Corinth. The envoy then went to the Peloponnese and called a meeting of the Achaean council. He praised the Achaeans for retaining an old decree forbidding the Macedonian kings to approach their territories, and emphasized that Rome considered Perseus an enemy. Violent conflict erupted in Thessaly and Perrhaebia (the land of the Perrhaebi, a tribe in northern Thessaly). This was exacerbated by a debt problem. Rome sent an envoy to try to defuse the situation. He managed to do so by addressing indebtedness "swollen by illegal interest" in both areas.Livy, The History of Rome, 42.2.1–2, 42.5.11–12, 42.5.5–6, 42.6.1–2.

Eumenes II of Pergamon, who had been in conflict with Macedon and who disliked Perseus, made a speech in the Roman senate with the aim of precipitating hostilities. The contents of the speech were kept secret and emerged only after war's end. He claimed that Perseus had been preparing for war since the day of his accession. He was respected and feared in the east and had influence on many kings. He mentioned Prusias of Bithynia, who was an enemy of Pergamon, asking for the hand of Perseus' daughter. He also mentioned that Antiochus IV, the new Seleucid king, betrothed his daughter to Perseus as an example of Perseus gaining influence among kings in the east, even though Antiochus had just renewed his father's alliance with Rome. The Boeotians had never made an alliance with Macedon. Members of the Achaean council threatened to call on Rome in their opposition to an alliance with Perseus. If not for this, such an alliance might have happened.

Perseus made preparations for war by storing corn for 30,000 troops, stockpiling weapons, and accumulating funds to hire 10,000 mercenaries in addition to many soldiers from Thrace. He seized some places and persuaded others through favour. Eumenes II claimed that if Rome ignored these developments, Perseus might attack Italy.Livy, The History of Rome, 42.10.1, 42.11–14.1.For Antiochus renewing the alliance with Rome see Livy, The History of Rome, 42.6.5–12.

A few days after Eumenes' speech, the senate received envoys from Perseus. They said that Perseus had not said or done anything hostile. However, the senators did not believe this and "their ears had been captured by Eumenes". They felt affronted when the leader of the embassy said that if Perseus saw that the Romans were bent on an excuse for war, he would respond with courage and that "the chances of war were the same for both sides and the issue was uncertain". When they returned to Macedon they told Perseus that the Romans were not preparing for war, but they were so embittered with him that they might do so soon. Perseus thought that this might be possible. He was determined to begin the war by shedding the blood of Eumenes, whom he hated, and called for Euander, a leader of Cretan mercenaries, and three Macedonian killers to arrange Eumenes' assassination.Livy, The History of Rome, 42.14.2–4, 15.1–4.

The cities of Greece and western and central Anatolia became convinced that Eumenes was steering Rome towards war. They sent emissaries to Rome. One of them was from Rhodes. It said that they felt sure that Eumenes had included Rhodes among those he accused of being friends of Perseus and, therefore, Rhodes had tried to confront Eumenes in the Roman senate. As this had failed, they accused Eumenes of trying to stir the Lycians (a people in western Anatolia under Eumenes' rule) against Rhodes and claimed that he was more oppressive than the Seleucid king.Before the Roman-Seleucid War (192–188 BC) the Seleucids were the masters of much of Asia. When Rome won the war, she gave the Seleucid territories in that area to Pergamon. The senators resented this claim. Hostility towards Eumenes by various Greek states made Rome more determined to favour him.Livy, The History of Rome, 14.5–10.

The plan to assassinate Eumenes failed during his visit to Delphi. Gaius Valerius Laevinus, who had been sent to investigate the situation in Greece and monitor Perseus, returned to Rome and supported Eumenes' allegations. He also bought a woman who was involved in the failed plot and a Roman who claimed that Perseus had tried to coerce him into poisoning ambassadors to Rome. Perseus was declared a public enemy, the Senate elected to wage war and dispatched an army to Apollonia on the western coast of Greece to occupy the coastal cities. The war was, however, put off. Eumenes also prepared for war.Livy, The History of Rome, 14.5–10, 15, 17–18.

Gentius, king of the Illyrians, brought himself under suspicion, but had not gone so far as to decide which side to support. The Thracian Cotys IV, king of the Odrysian Kingdom, the largest state in Thrace, had already declared for Macedon.Livy, The History of Rome, 29.11–12.

Preparations The consuls for 171 BC were Publius Licinius Crassus and Gaius Cassius Longinus. Macedon was assigned to Publius Licinius and the command of the fleet was assigned to praetor Gaius Lucretius.Livy, The History of Rome, 22.28, 32, 35.

Two legions were assigned for Macedon, each number 6,000 instead of the usual 5,200. Allied troops numbering 16,000 infantry and 800 cavalry accompanied them. Envoys were sent to confer with the Greek states. They received the support of Epirus, in western Greece, and Aetolia and Thessaly, in central Greece. The main Boeotian cities, though divided between a pro-Roman and a pro-Perseus faction, decided to break the treaty with Perseus to side with Rome. This broke up the league of Boeotian cities as some of them supported Perseus. In Rhodes a new leader, and some locally notable citizens such as Astymedes, persuaded the island to ally with Rome. Gentius, the king of Illyria, remained non–committal.Livy, The History of Rome, 42. 31.2–3, 32.5, 36–38.1–7, 43.4–10, 45, 46. 7–10.

A commission was sent to Greece. Perseus invited one of the commissioners, Marcius, for a meeting. He denounced Eumenes' allegations and others and claimed that his international relations were not aimed at preparing for war. Marcius advised him to send an embassy to Rome and arranged an armistice to guarantee safe passage. He did this because Rome was not ready for war. The army was preparing and had not yet gone to Greece.Livy, The History of Rome, 42. 38.8–10, 39–43.1–3, 46.1–6.

Many senators were pleased with the commissioners' diplomatic achievements. However, the older senators disapproved of the new policy of diplomacy, which they saw as not reflecting Romans' honour and courage and called for military action. As a result, 50 ships were sent to Greece and 2,000 troops were sent to occupy Larissa, the capital of Thessaly, to prevent Perseus from garrisoning it. Perseus' ambassadors arrived in Rome to argue for peace. The senate was not persuaded and they were ordered to leave Rome.Livy, The History of Rome, 42.47.

Fleet commander Gaius Lucretius set off with 40 ships. He received ten vessels from allies in southern Illyria at Dyrrhachium (modern Durrës, Albania) and 54 light vessels from Gentius, which he assumed had been assembled for the Romans. He reached Cephallania (Cephalonia, an island in the Ionic Sea) where he was joined by seven ships from Roman allies. He then went to Corfu. The consul crossed the sea from Italy and encamped with his force near Apollonia.Livy, The History of Rome, 42.48, 49.

Perseus assembled his whole army at Citium. He had 39,000 infantry, half of which were phalanxes (heavy infantry). The force included 3,000 Cretans, 3,000 men from Agrianes, Paeonia and Parstrymonia (a Thracian area around the River Strymon, in modern Bulgaria), 3,000 Thracians, 2,000 Gauls, 3,000 Macedonian cavalry, 1,000 Thracian cavalry, and 500 men from various Greek states.Livy, The History of Rome, 42.51.

171 BC Perseus marched to Perrhaebi in the northernmost district of Thessaly and seized the main towns north of the River Peneus, which crosses northern Thessaly: Cyretiae, Mylae, Elatia and Gonnus. He encamped at Sycurium, between Mount Ossa and the lower Peneus. It overlooked the plains of Thessaly and was not far from Larissa. Meanwhile, Publius Licinius had marched from Epirus on the west coast of Greece through arduous mountain passes and through Athamania, a kingdom allied with Perseus. He was lucky that they were not attacked, otherwise the green troops tired from their journey would have been defeated. He reached Thessaly and encamped at Tripolis Larisaia, five kilometres north of Larissa and further up the Peneus. He was joined by 4,000 infantry and 1,000 cavalry brought by Eumenes II of Pergamon and 1,500 infantry and 600 cavalry.Livy, The History of Rome, 42.53–55.