The Fourth Macedonian War (150–148 BC) was fought between Macedon, led by the pretender Andriscus, and the Roman Republic. It was the last of the Macedonian Wars, and was the last war to seriously threaten Roman control of Greece until the First Mithridatic War sixty years later.
The last Macedonian king of the Antigonid dynasty, Perseus, had been defeated and dethroned by the Romans in the Third Macedonian War in 168 BC. In the aftermath of the war, Rome took indirect control of the region through a system of client states, and imposed harsh terms to prevent Macedon from becoming a powerful state again. This system was successful in maintaining Roman hegemony for nearly two decades, but broke down when Andriscus, a Greek who bore a resemblance to Perseus, claimed to be the former king's son and re-established the Macedonian Kingdom with Thracian troops.
Andriscus was initially successful, defeating Roman clients and a Roman army sent to stop him, and conquering much of Thessaly. However, he was eventually defeated by another Roman army under Quintus Caecilius Metellus at the Second Battle of Pydna in 148 BC, severely weakening his position; he was subsequently pursued and eventually betrayed to the Romans. After settling a few subsequent minor rebellions, Rome took direct control of Macedon, making it a Roman province.
Background
Tensions between the Roman Republic and Macedon had first begun in 215 BC, when Philip V of Macedon allied himself with Rome's rival, Carthage, and declared war on Rome, sparking the First Macedonian War, an indecisive sideshow of the larger Second Punic War between Rome and Carthage. Soon after the end of the war with Carthage, a victorious Rome received multiple requests for assistance from a number of Greek polities and city-states which were afraid of Philip's ambition. Although war-weary from the recent Punic War, Rome agreed, and when Philip refused to accept their terms, they declared war on and defeated him in the Second Macedonian War of 200-197 BC, in which Philip was stripped of much territory and prestige, and forced to comply with Rome's demands. In the aftermath of this conflict, tensions developed between Rome and the Seleucid Empire, whose ambitious monarch, Antiochus III the Great, aimed to attain hegemony over Greece. Encouraged by the Aetolian League, Antiochus went to war with Rome in 192 BC, sparking the Roman-Seleucid War; it ended in a resounding Roman victory — Antiochus lost all his territory in Asia Minor and had to disband his fleet, pay a massive war indemnity and promise not to cross the Taurus Mountains, effectively relegating the Seleucids to an Asiatic power and ending their influence in Greece. Macedon regained some territory and influence on account of their cooperation with the Romans in this conflict, but high-handed Roman actions and Macedonian revanchism continued to stoke resentment in Philip.
Macedonian power continued to grow for the rest of Philip's reign, and this was continued by his talented son and successor, Perseus. Although Rome formally reaffirmed "friendship" with him, tensions continued to grow on account of reviving Macedonian power, Perseus' growing popularity with the Greeks and his successful diplomacy in the Greek world, in which he revived Macedonian influence and strengthened its position as a leading power once again. A tenuous peace continued until Eumenes II of Pergamon, a staunch Roman ally and Perseus' arch-rival, went to Rome in 172 BC and persuaded them that Perseus was a threat to Rome and the Greeks, and exhorted them to break his power. Finally, as Eumenes was returning to Pergamon, an assassination attempt on him, for which Perseus was blamed, resolved Rome in favour of war. The ensuing Third Macedonian War of 171-168 BC was hard-fought, but ended in a complete Roman victory and Perseus' surrender and imprisonment, establishing Rome's position as the sole hegemonic power in the Greek world.
The Greek world was harshly treated in the aftermath of the Roman victory; allies of Perseus were brutally repressed, while those suspected to have sympathized with Perseus became pariahs in the new Roman-dominated order. Rome took unprecedented measures to ensure that a revival of Macedonian power would be impossible — the ancient Macedonian monarchy was abolished and Perseus was exiled to an Italian city. Knowing that occupying Macedon would require military presence against barbarian tribes on Macedon's northern frontier, Rome decided against making it a province; instead, Macedon was broken up into four client republics, or merides, that paid tribute to Rome, with trade regulations and restrictions on interaction between the republics, as well as being forbidden to work Macedon's rich mines freely, and limiting them to possessing only such military forces as were necessary to deal with barbarian tribes to the north. Most of the former ruling elite was deported to Rome. Macedon also suffered from impoverishment, due to the fiscal restrictions imposed on it and the looting of treasuries by victorious Roman troops at the end of the Third Macedonian War in 168 BC. This, along with the effective destruction of the old social order, created great resentment among many sections of the populace.
However, Rome withdrew all its troops in 167 BC; thereafter, it left the Macedonian merides alone in their internal administration, not intervening even when appeals were made to it to resolve serious crises like a massacre of Macedonian officials in 163 BC. It has been suggested that Rome was seeking to satisfy the Macedonians with local autonomy, so that they would forget any sort of "national" identity; however, a general longing for monarchy persisted in Macedon, as the people had not yet adapted to democratic institutions, though a significant class of pro-Roman Macedonian republicans did develop, including those who had been persecuted by the old Antigonid monarchy. Some regulations were relaxed; for instance, the Macedonians were allowed to use their mines again from 158 BC, but resentment continued, including over those restrictions that remained, as well as the division of Macedon, leaving the situation ripe for the rise of pretenders to the old Antigonid throne.
Andriscus claims the throne
Around 154/153 BC, a Greek named Andriscus, who bore a resemblance to the Antigonids, began claiming that he was Philip, a now-obscure son of Perseus, and had been reared in secrecy by a foster family. The origins of this youth are unclear; ancient sources generally agree that he was a man of low origins, and that he hailed from Adramyttium in Aeolis in northwestern Asia Minor. He entered Macedonia in force to claim "his" throne, but was repulsed, presumably by the combined forces of three of the four client republics (the third republic had been forbidden from raising troops by the settlement of 167 BC).
At some point after this failure, he travelled to Syria and enlisted as a mercenary of the Seleucid monarch, Demetrius I Soter, and now began making his claims there. News of his claims spread, and after gaining enough notability, he appealed to Demetrius to help him regain his throne. Despite riotous support for him from the population of the Seleucid capital, Antioch, Demetrius refused to help him, and instead arrested him and had him shipped to Rome. The senate, however, remained complacent; although he was brought before the senate, he was simply exiled to an Italian city. He soon managed to escape from Italy and fled back to the Greek world, but the Romans remained unperturbed; they did not take him seriously.
He travelled to Miletus, where he tried to advance his claims further, attracting significant attention. Diodorus writes that when the leaders of Miletus learned about this, they arrested him and sought advice from visiting Roman envoys on what to do with him; the envoys were contemptuous of the pretender and told the Milesians that he was safe to release. After his release, he continued to try to achieve his aim of becoming king of Macedon. He travelled to Pergamon to meet with Callippa, a former concubine of Perseus, who gave him money and royal regalia. From there he went on to Byzantium, where he was received favourably and obtaining a significant following and a number of sympathizers. Helliesen proposes that the following that Andriscus built up in this period derived from Macedonians who had fled to Attalid territory after the Third Macedonian War and had been settled in garrisons in western Lydia.
Andriscus then travelled to Thrace, where he found allies and sympathy, especially from the Odrysian king Teres III, who was related to the Antigonids by marriage. Teres held a coronation ceremony for Andriscus, crowning him with a diadem, gave him a hundred troops, and introduced him to other Thracian leaders, including one Barsabas, who agreed to accompany him on his campaign to reclaim the Macedonian throne. He was also aided by some forces of Macedonian origin that Rubinsohn refers to as "émigré rabble".
Course of the war
Andriscus' conquest of Macedon
With this force, Andriscus invaded Macedonia in the spring of 149 BC. Initially, he failed to inspire much popular support for himself among the Macedonian populace, emboldening the Roman client republics in Macedon, and making the Roman Senate complacent about the risk posed by the pretender. There are indications that his first attempts to conquer Macedon were failures; he rallied his resources and tried again, meeting the forces of one of the republics in a battle on the banks of the Strymon river, defeating them soundly and conquering all of Macedonia west of the Strymon, including the old royal capital of Pella where took up residence, around the summer of 149 BC. At this point, he assumed the regnal name Philip. The Macedonian merides to the west continued to resist him, but were defeated in another battle on the west bank of the Strymon, after which the Macedonians seem to have accepted him as king.
His victories gained him the loyalty of the Macedonians; the people longed for monarchy and were willing to accept a ruler, and were eager to get rid of the artificial divisions and factional strife of the client republics. On the other hand, the neighbouring Greeks, including the historian Polybius, were taken by surprise; Polybius writes in astonishment of how the pretender who had "dropped from the skies" and, in his view, was a tyrant, could be accepted, let alone enthusiastically, by the Macedonians. Arthur M. Eckstein puts this view down to the fact that Polybius and the Greeks were part of a deep-rooted republican society, and could not comprehend the Macedonian longing for a hallowed monarchical past. Andriscus now attacked Thessaly; the Thessalian League appealed to the Achaean League for aid, knowing that any Roman involvement would be slow to come. They and the remnants of the pro-Roman Macedonian forces resisted him for some time, until Rome finally decided to send a legate, Scipio Nasica Corculum, to assess the situation.
Roman involvement
Scipio was sent with the purpose of negotiating a peaceful settlement; Gruen remarks that the fact that Rome believed in the possibility of a peaceful settlement at this stage shows that they were either out of touch with the situation or were not really committed to the settlement they had drawn up in the aftermath of the Third Macedonian War. It has been suggested that there is a possibility that he was sent before news of Andriscus' campaigns became widely known, and that he was simply sent to dissuade any Greek sympathy for Carthage, which Rome was planning to attack. Whatever the case, Scipio's attempts at diplomacy failed, probably because the Romans were unwilling to accept Andriscus' demand to be recognized as king of a unified Macedon. Instead, Scipio resorted to military action, and began to rally the forces of Thessalians and Achaeans that had already been fighting. With them, he managed to temporarily halt Andriscus' advance. Still, the Roman commander informed the Senate that direct military intervention would be needed to stop the pretender, as the situation was getting dire, with Andriscus already having conquered significant parts of Thessaly.
Thalna's defeat
In response to Scipio's report, the Senate appointed a praetor, Publius Juventius Thalna, to command a legion and settle the situation with military force. Thalna was probably reinforced by Greek contingents, and spent two or three months stabilizing the situation. However he seems to have underestimated Andriscus, not understanding that Andriscus' army had swelled dramatically since his enthronement, including contingents of both Macedonians and Thracians. Thalna's attempt to invade Macedonia via Thessaly was intercepted by Andriscus at an unspecified location near the borders of Macedon in late 149 or early 148 BC; details of the engagement are scarce, but Thalna was killed and his army almost annihilated, with the survivors escaping under the cover of night. It was the worst defeat Rome had suffered so far in their campaigns against Hellenistic powers, and had massive psychological impact in both Greece and Rome.