The history of Epirus was very similar in many aspects to that of Macedonia: located at the northern borders of the Greek world, this region of the Balkans (more or less corresponding to modern Albania) was strongly influenced by both the Illyrians and Greeks. As with Macedonia, the original semi-barbarous Epirus gradually transformed into a `hellenized’ kingdom, thus becoming one of the most significant Hellenistic states. Traditionally, Epirus had always been inhabited by three main tribes: the Chaonians in the north, the Molossians in the centre and the Thesprotians in the south. Until 370 BC, these three tribes were not organized into a real state and were frequently at war with each other. Unlike Greece, Epirus had no cities: all the Epirotes lived in small villages dispersed across the countryside. The three tribes of Epirus had originally been nomadic groups, constantly at war against the Illyrians from the north. This political situation continued to exist until 370 BC, when the Molossians (the most important of the three Epirote tribes) started to expand at the expense of the other two tribal groups. After some years of internal wars, the Molossians were finally able to unify Epirus and form a centralized kingdom that was ruled by the Molossian royal family of the Aecides. After some decades, the new Kingdom of Epirus decided to form an alliance with the Kingdom of Macedonia. The latter was becoming increasingly powerful militarily and the Epirotes needed an ally against the Illyrians. As a result, Neoptolemus I, the first monarch of unified Epirus, married his daughter, Olympia, to Philip of Macedon in 357 BC. When Neoptolemus died, the throne was inherited by his brother, Arybbas, who was later driven into exile by Philip of Macedon and replaced by Neoptolemus’ son, Alexander. The latter was brother of Olympia and thus uncle of Alexander the Great. While his more famous nephew was conquering the Persian Empire, Alexander of Epirus decided to obtain some glory for himself by launching a military campaign in Italy. Epirus was very near to southern Italy and thus became increasingly involved in the local conflicts of the peninsula. In 334 BC, Alexander of Epirus landed in Italy, officially to help the important Greek colony of Taras in its war against the Italic tribes of the Lucanians and Bruttii. The campaign organized to emulate Alexander the Great, however, was a failure and Alexander of Epirus was killed in battle in 331. In the following decades, as we have seen, the Kingdom of Epirus was involved in the Wars of the Diadochi and thus temporarily abandoned any ambition of expansion in Italy.
This situation only changed in 295 BC with the rise to the Epirote throne of Pyrrhus, who had great political ambitions. As we have seen, during the first part of his reign Pyrrhus did everything possible to conquer the Kingdom of Macedonia for himself, but the superior military capabilities of his enemies prevented him from achieving any significant success. As a result, with his original ambitions frustrated, Pyrrhus decided to follow the example of Alexander of Epirus and launched a great military expedition to `support’ Taras in southern Italy. The campaign on the peninsula, however, proved to be very difficult and costly for the Epirotes, who had to face the military power of Rome: the Kingdom of Epirus was the first Hellenistic state to fight against the Romans in battle. After achieving very little, Pyrrhus moved to Sicily to ally himself with the Greek cities of the island against the Carthaginians, who were expanding at the expense of the Greeks, with the clear intention of conquering the whole island. Pyrrhus was able to achieve remarkable success in Sicily, almost expelling the Carthaginians from the island. However, the Greek cities rebelled against him because they understood that the Epirote king only wanted to conquer Sicily for himself. Obliged to abandon Sicily, Pyrrhus marched against the Romans, but was decisively defeated at the Battle of Beneventum (275 BC), after which he decided to abandon Italy and leave Taras to face the Romans alone. Pyrrhus was credited by the Romans with teaching them how to lay out camps.
In constant search of glory, Pyrrhus resumed his political ambitions over Macedonia and Greece, soon starting a new war against Antigonus Gonatas with the objective of conquering the throne of Macedonia. He also marched into Greece, with the aim of placing some of his allies at the head of important cities like Sparta or Argos. In 272 BC, during some harsh street-fighting in Argos, Pyrrhus was killed, after which the Kingdom of Epirus quickly lost any ambition to be a military superpower and became a minor participant in the Hellenistic political struggles. In 233, the last exponent of the Aecides royal family died without heirs, leaving Epirus with no ruler. Shortly after, the Epirotes decided to transform their kingdom into a federal republic known as the Epirote League with a sort of parliament. The League remained neutral during the first two wars fought between Rome and Macedonia, but was involved in the last, decisive conflict of 171-168 BC, when the Molossians sided with Macedonia while the other two tribes sided with Rome. After the end of the war, in 167, the territories of the Molossians were annexed by Rome. The Chaonians and Thesprotians were soon transformed from allies into subjects of the Roman Republic, resulting in the disappearance of Epirus as an independent state.
Until the ascendancy of Alexander of Epirus, Epirote military forces were simply made of irregular tribal levies, which were very similar to those of the Illyrians. These contingents of light infantrymen, presumably equipped as psiloi skirmishers or traditional peltasts, were transformed into regular troops shortly before the first Epirote expedition to Italy. Alexander of Epirus was a personal friend and loyal ally of Philip of Macedon. He had spent most of his early life as a hostage at the Macedonian royal court, so it is highly probable that he learned how to reorganize an army from Philip of Macedon and then decided to apply the latter’s military reforms in his country. Epirus was mountainous and inhospitable, with a terrain that was perfect for loose formations of light infantry and not for tightly packed heavy phalangists. In addition, unlike Macedonia or Thessaly, Epirus could field a small cavalry force formed by the few nobles of the country. Under Pyrrhus, however, the Epirote Army soon transformed into a significant military force thanks to the major use of contingents provided by allies or mercenaries. When the ambitious king landed in Italy, his expeditionary army comprised the following: 23,000 infantrymen, 2,000 archers, 500 slingers, 3,000 cavalrymen and twenty war elephants. It is interesting to note that Pyrrhus was strongly supported by Ptolemy Keraunos during the organization of his Italian expedition: the usurper of Lysimachus’ dominions and army sent him the twenty war elephants and 5,500 excellent veteran soldiers. Of these, 5,000 were Macedonian phalangists who formed the real core of Pyrrhus’ infantry. The heavy infantry of the Epirote Army was completed by 2,000 phalangists from the city of Ambracia (the only significant urban centre of Epirus, conquered by Pyrrhus, who made it the new capital of his kingdom) and 12,000 `real’ Epirotes (Molossians, Chaonians and Thesprotians) also equipped as phalangists. The 12,000 Epirotes were organized into three different units of 4,000 men, corresponding to the three main tribal groups of Epirus. The remaining 4,000 infantry were all lightly equipped Greek mercenaries: Aitolians, Athamanians and Acarnanians. The 3,000 cavalry comprised 2,000 heavy cavalrymen from Epirus and 1,000 light cavalrymen. The 2,000 heavy cavalry was formed by the aristocracy of the kingdom, as in Macedonia, apparently comprising an elite agema squadron of 400 men (acting as the mounted bodyguard of the king) and eight `line’ squadrons with 200 soldiers each. The 1,000 light cavalry included 500 Thessalians sent by Ptolemy Keraunos and 500 Greek mercenaries (Aitolians, Athamanians and Acarnanians). After its arrival in Italy, the army was supplemented by the military forces of Taras and large numbers of allied/mercenary Italic warriors from several different peoples. Later, during his Sicilian campaign, Pyrrhus could count on massive numbers of local allies and mercenaries provided by the Greek cities of the island: Syracuse sent him 10,000 infantry and 400 cavalry. Most of the Italic and Sicilian mercenaries recruited during the campaigns in southern Italy were paid by Pyrrhus only thanks to the economic resources of Taras. After returning to Epirus for his last military enterprise, the ambitious king had to rebuild his army, recruiting 5,000 Galatians who had already served under Antigonus Gonatas as mercenaries (these Celts had remained in Greece after their failed invasion).
In Greece Pyrrhus relied chiefly on Epeirot troops, as without the resources of Taras he could probably afford few mercenaries. Twice he was briefly king of Macedon and Thessaly and could use their resources. He was at times allied with Aitolia, controlled Akarnania, and some sources say that in his last campaign against Sparta he was allied with Elis and Messene, though this is not certain. In 274-3 he hired at least 2,000 Gauls, who fought well but lost Macedonian support by looting indiscriminately, plundering the Macedonian royal tombs. They formed part of an army of 25,000 foot, 2,000 horse and 24 elephants.
After Pyrrhus’ death Epirus reverted to minor power status, first under his descendants and then as a republic, no doubt mostly using citizen troops. However we do have an account of one singularly unfortunate experience with mercenaries. A force of 800 Gauls, allegedly exiled by their own countrymen, had served Carthage in Sicily; they pillaged one city they were garrisoning, tried to betray another, and deserted to Rome. In Roman service they sacked a temple, and so were ejected from Italy as soon as possible. The Epirots hired this band of desperadoes and set them to garrison the capital Phoinike. True to form, the Gauls betrayed the city to a fleet of passing Illyrian pirates, and the entire population of Phoinike was enslaved! As Polybios says “no people, if wise, should ever admit a garrison stronger than their own forces, especially if composed of barbarians”.