Alexander's Balkan campaign

The Balkan campaign of Alexander the Great took place in 335 BC, against a number of rebellious vassals of the Macedonian kingdom. Alexander successfully pacified each in turn, leaving him free to begin the long planned invasion of Persia.

Background
In 336 BC, while attending the wedding of his daughter by Olympias, Cleopatra and Olympias' brother, Alexander I of Epirus at Aegae, Philip II was assassinated by the captain of his bodyguard, Pausanias. Philip's son, and previously designated heir, Alexander was proclaimed king by the Macedonian noblemen and army.

News of Philip's death roused many states into revolt including Thebes, Athens, Thessaly and the Thracian tribes to the north of Macedon. When news of the revolt reached Alexander he responded quickly. Though his advisors advised him to use diplomacy, Alexander mustered the Macedonian cavalry of 3,000 men and rode south towards Thessaly, Macedon's immediate neighbor to the south. When he found the Thessalian army occupying the pass between Mount Olympus and Mount Ossa, he had the men ride through Mount Ossa and, when the Thessalians awoke, they found Alexander at their rear. The Thessalians surrendered and added their cavalry to Alexander's force as he rode down towards the Peloponnese.

Alexander stopped at Thermopylae, where he was recognised as the leader of the Sacred League before heading south to Corinth. Athens sued for peace and Alexander received the envoy and pardoned anyone involved with the uprising. At Corinth, he was given the title 'Hegemon' of the Greek forces against the Persians. While at Corinth, he heard the news of the Thracian rising to the north.

Thrace
Before crossing to Asia, Alexander wanted to safeguard his northern borders and, in the spring of 335 BC, he advanced into Thrace to deal with the revolt, which was led by the Illyrians and Triballi. He was reinforced along the way by the Agriani, a Thracian tribe under the command of Alexander's friend, Langarus. The Macedonian army marched up to Mount Haemus, where they met a Thracian garrison manning the heights. The Thracians had constructed a palisade of carts, which they intended to throw upon the approaching Macedonians. Alexander ordered his heavy infantry to march in loose formation and, when the carts were thrown, to either open the ranks or lay flat on the ground with their shields over them. The Macedonian archers opened fire and when the Macedonian infantry reached the top of the mountain they routed the Thracians.

Meanwhile, a large Triballian army led by their king, Syrmus, advanced upon the Macedonian rear. The Triballians retreated to a gorge, where they were drawn out by Alexander's light infantry. On the open ground, they were crushed by Alexander's infantry and cavalry, leaving behind 3,000 dead. The Macedonians marched to the Danube River where they encountered the Getae tribe on the opposite shore. As Alexander's ships failed to enter the river, Alexander's army made rafts out of their leather tents. A force of 4,000 infantry and 1,500 cavalry crossed the river, to the amazement of the Getae army of 14,000 men. The Getae army retreated after the first cavalry skirmish, leaving their town to the Macedonian army.

Illyria
News reached Alexander that Cleitus the Dardanian, and King Glaukias of the Taulanti were in open revolt against Macedonian authority. Alexander headed to the insurgents but the Dardanians had occupied a Macedonian border fortress , Pelium just before he arrived.

Autariatae were lying in wait to attack Alexander but were disposed of by Langaros. Alexander managed to prevent the Dardani from linking with the Taulanti. Cleitus withdrew into the city and was pinned after feigning an attack on Alexander.

The following day, Glaukias arrived with his army to relieve the town. Philotas, one of Alexander's friends and generals, was trapped by the Taulanti while foraging. When Alexander heard of his friend's predicament he rushed in with his army and managed to frighten Glaukias off attacking Philotas.

Alexander and his army were trapped between the Dardani and the Taulanti, who each held high ground. When Alexander's army moved towards the Taulanti threat, yelling their war cries, the Taulanti fled from the heights and went into the town. After noticing Pelium's lack of defenses, Alexander feigned a retreat, and, in the night, stormed the town, forcing Cleitus and Glaukias to flee with their armies, leaving Alexander's northern frontier secure.

Thebes
While he was triumphantly campaigning north, the Thebans and Athenians rebelled once more. Alexander reacted immediately, but, while the other cities once again hesitated, Thebes decided to resist with the utmost vigor. This resistance was useless, however, as the city was razed to the ground amid great bloodshed and its territory divided between the other Boeotian cities. Moreover, the Thebans themselves were sold into slavery. Alexander spared only priests, leaders of the pro-Macedonian party and descendants of Pindar, whose house was the only one left standing. The end of Thebes cowed Athens into submission. According to Plutarch, a special Athenian embassy, led by Phocion, an opponent of the anti-Macedonian faction, was able to persuade Alexander to give up his demand for the exile of leaders of the anti-Macedonian party, most particularly Demosthenes.

Aftermath
With the destruction of Thebes, the Macedonian possessions and vassals in Europe were once again quiscent to Alexander's rule. Alexander was now finally free to undertake the Persian campaign which had been planned for so long by his father.