His mother was Phila, the daughter of Antipater, who had controlled Macedonia and the rest of Greece since 334 BC and was recognized as regent of the empire, which in theory remained united.

After coming closer than anyone to reuniting the empire of Alexander, Antigonus Monophthalmus was defeated and killed in the great Battle of Ipsus in 301 BC and the territory he formerly controlled was divided among his enemies, Cassander, Ptolemy, Lysimachus, and Seleucus.

Hoping to seize Lysimachus' territories in Thrace and Asia, Demetrius delegated command of his forces in Boeotia to Antigonus and immediately marched north.

He aimed at nothing less than the revival of Alexander's empire and started making preparations on a grand scale, ordering the construction of a fleet of 500 ships, many of them of unprecedented size.

Leaving Antigonus in charge of the war in Greece, he assembled all his ships and embarked with 11,000 infantry and all his cavalry to attack Caria and Lydia, provinces of Lysimachus.

At this point, he wrote to his son and to his commanders in Athens and Corinth telling them to henceforth consider him a dead man and to ignore any letters they might receive written under his seal.

When Antigonus heard that his father's remains were being brought to him, he put to sea with his entire fleet, met Seleucus's ships near the Cyclades, and took the relics to Corinth with great ceremony.

Antigonus decided the time was ripe to take back his father's kingdom, but when he marched north, Ptolemy Keraunos defeated his army.

In the winter of 279 BC, a great horde of Gauls under their leader Brennus descended on Macedonia from the north, crushed Ptolemy's army and killed him in battle, starting two years of complete anarchy in the kingdom.

In 278 BC a Greek army with a large Aetolian contingent checked the Gauls at Thermopylae and Delphi, inflicting heavy casualties and forcing them to retreat.

During the negotiations Ameinias had 2,000 of his men launch a surprise attack on the city with specially prepared ladders of the right height, they gained possession of the walls and summoned Antigonus.

[4] Pyrrhus, king of Epirus, Macedonia's western neighbour, was a general of mercurial ability, widely renowned for his bravery, but he did not apply his talents sensibly and often snatched after vain hopes, so that Antigonus used to compare him to a dice player, who had excellent throws, but did not know how to use them.

Pyrrhus had been drained by his recent wars in Sicily, and by the earlier "Pyrrhic victories" over the Romans, and thus decided to end his campaign in Italy and return to Epirus.

This encouraged him to look for another war, so the next year, after adding a force of Gallic mercenaries to his army, he invaded Macedonia with the intention of filling his coffers with plunder.

Making himself master of several towns and being joined by two thousand deserters, his hopes started to grow and he went in search of Antigonus, attacking his army in a narrow pass and throwing it into disorder at the Battle of the Aous River.

Taking possession of Aegae, the ancient capital of Macedonia, he installed a garrison of Gauls, who greatly offended the Macedonians by digging up the tombs of their kings and leaving the bones scattered about as they searched for gold.

These reinforcements stiffened resistance, and Pyrrhus, finding that he was losing men to desertion every day, broke off the attack and started to plunder the country.

When Pyrrhus learned this, he encamped about Nauplia and the next day dispatched a herald to Antigonus, calling him a coward and challenging him to come down and fight on the plain.

Fearing that the gates would be too narrow for his troops to easily exit the city, he sent a message to his son, Helenus, who was outside with the main body of the army, asking him to break down a section of the walls.

This beast surged against the tide of fugitives, crushing friend and foe alike, until it found its dead master, whereupon it picked him up, placed him on its tusks, and went on the rampage.

Alexander seems to have died about 242 BC, leaving his country under the regency of his wife Olympias who proved anxious to have good relations with Epirus' powerful neighbour, as was sanctioned by the marriage between the regent's daughter Phthia and Antigonus' son and heir Demetrius.

With the restoration of the territories captured by Pyrrhus, and with grateful allies in Sparta and Argos, and garrisons in Corinth and other cities, Antigonus securely controlled Macedonia and Greece.

To support the Athenians and prevent the power of Antigonus from growing too much, Ptolemy II Philadelphus, the king of Egypt, sent a fleet to break the blockade.

After two years in which little changed, Antiochus II Theos, the new Seleucid king, made a military agreement with Antigonus, and the Second Syrian War began.

Under the combined attack, Egypt lost ground in Anatolia and Phoenicia, and the city of Miletus, held by its ally, Timarchus, was seized by Antiochus II.

Two years later, however, the Egyptian interfered again, inducing with his subsidies the Macedonian governor of Corinth and Euboea, Alexander, son of Craterus, to challenge his king, seeking independence as a tyrant.

In 251 BC, Aratus, a young nobleman in the city of Sicyon, expelled the tyrant Nicocles, who had ruled with the acquiescence of Antigonus, freed the people, and recalled the exiles.

[10] Diogenes Laertius reproduces a brief series of letters between Zeno and Antigonus, in which he asked the Stoic to attend his court and help guide him in virtue, for the benefit of the Macedonian people.

It is also said of him that he gained the affection of his subjects by his honesty and his cultivation of the arts,[16] which he accomplished by gathering round him distinguished literary men, in particular philosophers, poets, and historians.

The life of Antigonus is the basis of the story line of the libretto Antigono by Pietro Metastasio, first set to music by Johann Adolph Hasse in 1744.