Connection between Seleucus and Demetrius Poliorcetes, by the marriage of the former with the beautiful Stratonice, daughter of the latter; made with the view of counterbalancing a similar connection between Ptolemy and Lysimachus; Lysimachus and his son Agathocles having united themselves with two daughters of Ptolemy. 6. The eighteen years of tranquillity enjoyed by Asia after the battle of Ipsus, prove that Seleucus was one of the few followers of Alexander who had any genius for the arts of peace. He either founded or embellished a vast number of cities, the most important of which were the capital, Antiochia in Syria, and the two Seleucias, one on the Tigris, the other on the Orontes: the flourishing prosperity of several of these places was the result of the restoration of eastern trade; new channels for which appear to have been opened at this period on the main streams of Asia, and more particularly on the Oxus. 7. The home department of his empire was organized into satrapies, of which there were seventy-two. But Alexander's maxim, "to give the satrapies to natives," was wholly forgotten by his followers; and the Seleucidae were not long before they experienced the evil consequences of swerving from that practice. Under such a prince as Seleucus scarce any kingdom could of itself fall to pieces; but the king himself paved the way for the dismemberment of his empire, by ceding Upper Asia, together with his consort Stratonice, to his son Antiochus; not, however, without the previous approbation of the army. 8. War with Lysimachus, kindled by ancient jealousy, and now fomented by family feuds. The battle of Curopedion cost Lysimachus his throne and his life; and Asia Minor became a part of the Syrian realm. But as Seleucus was crossing over to Europe, to add Macedonia to his dominions, he fell by the hand of an assassin, Ptolemy Ceraunus, and with him the splendour of his kingdom was extinguished. 9. The reign of his son, Antiochus I. surnamed Soter, seemed not unprosperous, inasmuch as the empire preserved its former extension; but in any state founded upon conquest, the failure of new attempts at an increase of territory is a sure token of approaching ruin; and this was the case here.--In such a state, the more immediately all depends on the person of the ruler, the more rapid and sensible are the effects of degeneration in a family like that of the Seleucidae.