It would, perhaps, have been difficult for the Seleucid princes, even had they desired it, to pursue a policy of absolute abstention in the wars of their western neighbors.  So long as they were resolute to maintain their footing on the right bank of the Euphrates, in Phrygia, Cappadocia, and upper Syria, they were of necessity mixed up with the quarrels of the west.  Could they have been content to withdraw within the Euphrates, they might have remained for the most part clear of such entanglements; but even then there would have been occasions when they must have taken the field in self-defence.  As it was, however, the idea of abstention seems never to have occurred to them.  It was the fond dream of each “Successor” of Alexander that in his person might, perhaps, be one day united all the territories of the great Conqueror.  Seleucus would have felt that he sacrificed his most cherished hopes if he had allowed the west to go its own way, and had contented himself with consolidating a great power in the regions east of the Euphrates.

And the policy of the founder of the house was followed by his successors.  The three Seleucid sovereigns who reigned prior to the Parthian revolt were, one and all, engaged in frequent, if not continual, wars with the monarchs of Egypt and Asia Minor.  The first Seleucus, by his claim to the sovereignty of Lower Syria, established a ground of constant contention with the Ptolemies; and though he did not prosecute the claim to the extent of actual hostility, yet in the reign of his son, Antiochus I., called Soter, the smothered quarrel broke out.  Soter fomented the discontent of Cyrene with its subjection to Egypt, and made at least one expedition against Ptolemy Philadelphus in person (B.C. 264).  His efforts did not meet with much success; but they were renewed by his son, Antiochus II., surnamed “the God”, who warred with Philadelphus from B.C. 260 to B.C. 250, contending with him chiefly in Asia Minor.  These wars were complicated with others.  The first Antiochus aimed at adding the kingdom of Bithynia to his dominions, and attacked successively the Bythynian monarchs, Zipcetas and Nicomedes I. (B.C. 280-278).  This aggression brought him into collision with the Gauls, whom Nicomedes called to his aid, and with whom Antiochus had several struggles, some successful and some disastrous.  He also attacked Eumenes of Pergamus (B.C. 263), but was defeated in a pitched battle near Sardis.  The second Antiochus was not engaged in so great a multiplicity of contests; but we hear of his taking a part in the internal affairs of Miletus, and expelling a certain Timachus, who had made himself tyrant of that city.  There is also some ground for thinking that he had a standing quarrel with the king of Media Atropatene.  Altogether it is evident that from B.C. 280 to B.C. 250 the Seleucid princes were incessantly occupied with wars in the west, in Asia Minor and in Syria Proper, wars which so constantly engaged them