The effects of the battle of Ipsus were speedily felt in Greece. The Athenians passed a decree proclaiming themselves neutral, and excluding both the belligerent parties from Attica. Demetrius, retiring with the remnant of his defeated army, and embarking at Ephesus to sail to Athens, was met on the voyage by Athenian envoys, who respectfully acquainted him that he would not be admitted. At the same time, his wife Didamia, whom he had left at Athens, was sent away by the Athenians under an honourable escort to Megara, while some ships of war which he had left in the Piræus were also restored to him. Demetrius, indignant at this unexpected defection of a city which had recently heaped upon him such fulsome adulation, was still further mortified by the loss of most of his other possessions in Greece. His garrisons were for the most part expelled, and the cities passed into Cassandrian keeping or dominion. His fortunes were indeed partially restored by concluding a peace with Seleucus, who married his daughter. This alliance withdrew Demetrius to Syria, while Greece appears to have fallen more and more under the Cassandrian parties. It was one of these partisans, Lachares, who, seconded by Cassander’s soldiers, acquired a despotism at Athens such as had been possessed by the Phalerean Demetrius, but employed in a manner far more cruel and oppressive.
Various exiles from his tyranny invited Demetrius Poliorcetes, who passed over again from Asia into Greece, recovered portions of Peloponnesus, and laid siege to Athens. He blocked up the city by sea and land, so that the pressure of famine presently became intolerable. Lachares having made his escape, the people opened their gates to Demetrius, not without great fear of the treatment awaiting them. But he behaved with forbearance, and even with generosity. He spared them all, supplied them with a large donation of corn, and contented himself with taking military occupation of the city, naming his own friends as magistrates. He put garrisons, however, not only into Piræus and Munychia, but also into the hill called Museum, a part of the walled circle of Athens itself (298 B.C.).
While Demetrius was thus strengthening himself in Greece, he lost all his footing both in Cyprus, Syria, and Cilicia, which passed into the hands of Ptolemy and Seleucus. New prospects however were opened to him in Macedonia by the death of Cassander (his brother-in-law, brother of his wife Phila) and the family feuds supervening thereupon. Philippus, eldest son of Cassander, succeeded his father, but died of sickness after something more than a year. Between the two remaining sons, Antipater and Alexander, a sanguinary hostility broke out. Antipater slew his mother Thessalonice, and threatened the life of his brother, who in his turn invited aid both from Demetrius and from the Epirotic king Pyrrhus. Pyrrhus being ready first, marched into Macedonia, and expelled Antipater; receiving as his recompense the territory called Tymphæa (between Epirus and Macedonia) together with Acarnania, Amphilochia, and the town of Ambracia, which became henceforward his chief city and residence. Antipater sought shelter in Thrace with his father-in-law Lysimachus; by whose order, however, he was presently slain. Demetrius, occupied with other matters, was more tardy in obeying the summons; but, on entering into Macedonia, he found himself strong enough to dispossess and kill Alexander (who had indeed invited him, but is said to have laid a train for assassinating him), and seized the Macedonian crown; not without the assent of a considerable party, to whom the name and the deeds of Cassander and his sons were alike odious.
[294-279 B.C.]
Demetrius became thus master of Macedonia, together with the greater part of Greece, including Athens, Megara, and much of Peloponnesus. He undertook an expedition into Bœotia, for the purpose of conquering Thebes; in which attempt he succeeded, not without a double siege of that city. But Greece as a whole was managed by Antigonus (afterwards called Antigonus Gonatas) son of Demetrius, who maintained his supremacy unshaken during all his father’s life-time; even though Demetrius was deprived of Macedonia by the temporary combination of Lysimachus with Pyrrhus, and afterwards remained (until his death in 283 B.C.) a captive in the hands of Seleucus. After a brief possession of the crown of Macedonia successively by Seleucus, Ptolemy Ceraunus, Meleager, Antipater, and Sosthenes—Antigonus Gonatas regained it in 277 B.C. His descendants, the Antigonid kings, maintained it until the battle of Pydna in 168 B.C.; when Perseus, the last of them, was overthrown, and his kingdom incorporated with the Roman conquests.