6. The two remaining sons, Antipater and Alexander, soon worked their own destruction. Antipater having murdered his own mother Thessalonice, on account of the favour she showed his brother, was obliged to flee; he applied for help to his father-in-law Lysimachus of Thrace, where he soon after died. Meanwhile Alexander, fancying that he likewise stood in need of foreign assistance, addressed himself to Pyrrhus, king of Macedonia, and to Demetrius Poliorcetes, both of whom obeyed the call only with the expectation of being paid. After various snares reciprocally laid for each other, the king of Macedonia was murdered by Demetrius, and with him the race of Antipater became extinct. 7. The army proclaimed Demetrius king; and in his person the house of Antigonus ascended the throne of Macedonia, and, after many vicissitudes, established their power. His seven years' reign, in which one project succeeded the other, was a constant series of wars; and as he never could learn how to bear with good fortune, his ambition was at last his ruin. The kingdom of Demetrius comprised Macedonia, Thessaly, and the greatest part of the Peloponnesus; he was also master of Megara and Athens.--Twofold capture of Thebes, which had been rebuilt by Cassander, 293, and 291; unsuccessful attempt upon Thrace, 292. His war with Pyrrhus, 290, in whom men fancied they beheld another Alexander, had already alienated the affections of the Macedonians; but his grand project for the recovery of Asia induced his enemies to get the start of him; and the hatred of his subjects compelled him secretly to escape to Peloponnesus, to his son Antigonus, 287. Athens, taking advantage of his misfortunes, drove out the Macedonian garrison, and, by the election of archons, reestablished her ancient constitution; although Demetrius laid siege to the town, he allowed himself to be pacified by Crates. Having once more attempted to prosecute his plans against Asia, he was obliged, 286, to surrender to Seleucus his father-in-law, who, out of charity, kept him till the day of his death, 284. 8. Two claimants to the vacant throne now arose, viz. Pyrrhus of Epirus and Lysimachus of Thrace; but although Pyrrhus was first proclaimed king, with the cession of half the dominions, he could not, being a foreigner, support his power any longer than the year 286, when he was deposed by Lysimachus.