ANTIOCHUS I  . SOTER (324 or 323–262) was half a Persian, his mother Apame being one of those eastern princesses whom Alexander had given as wives to his generals in 324 . On the assassination of his father (281), the task of holding together the empire was a formidable one, and a revolt in Syria broke out almost immediately . With his father's murderer, Ptolemy, Antiochus was soon compelled to make peace, abandoning apparently Macedonia and Thrace . In Asia Minor he was unable to reduce Bithynia or the Persian dynasties which ruled in Cappadocia . In 278 the Gauls broke into Asia Minor, and a victory which Antiochus won over these hordes is said to have been the origin of his title of Soter (Gr. for " saviour ") . At the end of 275 the question of Palestine, which had been open between the houses of Seleucus and Ptolemy since the partition of 301, led to hostilities (the " First Syrian War ") . It had been continuously in Ptolemaic occupation, but the house of Seleucus maintained its claim . War did not materially change the out-lines of the two kingdoms, though frontier cities like Damascus and the coast districts of Asia Minor might change hands . About 262 Antiochus tried to break the growing power of Pergamum by force of arms, but suffered defeat near Sardis and died soon afterwards (262) . His eldest son Seleucus, who had ruled in the east as viceroy from 275 (?) till 268/7, was put to death in that year by his father on the charge of rebellion (Wace, J.H.S. xxv., 1905, p . 101 f.) .

He was succeeded (261) by his second son ANTIOCHUS II . THEOS (286-246), whose mother was the Macedonian princess Stratonice, daughter of

Demetrius Poliorcetes . War with Egypt still went on along the coasts of Asia Minor (the " Second Syrian War ") . Antiochus also made some attempt to get a footing in Thrace . About 250 peace was concluded between Antiochus and Ptolemy II., Antiochus repudiating his wife Laodice and marrying Ptolemy's daughter Berenice, but by 246 Antiochus had left Berenice and her infant son in Antioch to live again with Laodice in Asia Minor . Laodice poisoned him and proclaimed her son SELEUCUS II . CALLINICUS(reigned 246–227) king, whilst her partisans at Antioch made away with Berenice and her son . Berenice's brother, Ptolemy III., who had just succeeded to the Egyptian throne, DYNASTY at once invaded the Seleucid realm and marched victoriously to the Tigris or beyond, receiving the submission of the eastern provinces, whilst his fleets swept the coasts of Asia Minor . In the interior of Asia Minor Seleucus maintained himself, and when Ptolemy returned to Egypt he recovered Northern Syria and the nearer provinces of Iran . In Asia Minor his younger brother Antiochus Hierax was put up against him by a party to which Laodice herself adhered . At Ancyra (about 235 ?) Seleucus sustained a crushing defeat and left the country beyond the Taurus to his brother and the other powers of the peninsula . Of these Pergamum now rose to greatness under Attalus I., and Antiochus Hierax perished as a fugitive in Thrace in 228/7 .

A year later Seleucus was killed by a fall from his

horse . His elder son, SELEUCUS III . SOTER (reigned 227–223), took up the task of reconquering Asia Minor from Attalus, but fell by a conspiracy in his own camp .