His return to Babylon in that year was afterwards officially regarded as the beginning of the Seleucid empire. Master of Babylonia, Seleucus at once proceeded to wrest the neighbouring provinces of Persis, Susiana and Media from the nominees of Antigonus. A raid into Babylonia conducted in 311 by Demetrius, son of Antigonus, did not seriously check Seleucus's progress. Whilst Antigonus was occupied in the west, Seleucus during nine years (311-302) brought under his authority the whole eastern part of Alexander's empire as far as the Jaxartes and Indus. In 305, after the extinction of the old royal line of Macedoinia, Seleucus, like the other four principal Macedonian chiefs, as sumed the style of king. He attempted to recover Alexander's conquests in India, but with Antigonus threatening in the west he made peace with Chandragupta in 302, ceding him territory in Afghanistan for 50o elephants. In 301 he and Lysimachus defeated Antigonus at Ipsus in Asia Minor. A new partition of the empire followed, by which Seleucus added to his kingdom Syria, and perhaps some regions of Asia Minor. The possession of Syria gave him an opening to the Mediterranean, and he founded here his new capital, Antioch, on the Orontes. Seleucia continued to be the capital for the eastern satrapies. About 293 he installed his son Antiochus there as viceroy. Demetrius fell in 285, and an invitation by Ptolemy Ceraunus gave him a chance to remove his last rival, Lysimachus, who was defeated and killed at Corupedion in Lydia (281). Seleucus now had the whole of Alex ander's empire but Egypt in his hands. He left Asia to Antiochus, and crossed over to take possession of Macedonia. He reached the Chersonese to be murdered by Ptolemy near Lysimachia (281).
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, Anti ochus 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 them 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"). About 262 Antiochus tried to break the growing power of Pergamum, but suffered defeat near Sardis and died soon afterwards (262).
261-223 B.C.—He was succeeded (261) by his second son ANTIOCHUS II. THEOS (286-246), whose mother was the Mace donian 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 25o peace was concluded be
tween 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 king, whilst her partisans at Antioch made away with Berenice and her son. Berenice's brother, Ptolemy III., who had just suc ceeded to the Egyptian throne, at once invaded the Seleucid realm and annexed 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. At Ancyra (about 235?) Seleucus was defeated by his younger brother Antiochus Hierax, supported by Laodice, 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.
Antiochus III. the Great (223-187).—Callinicus's younger son, a youth of about eighteen, now succeeded to a disorganized kingdom (223). Not only was Asia Minor detached, but the further eastern provinces had broken away, Bactria under the Greek Diodotus (q.v.), and Parthia under the nomad chieftain Arsaces. Soon after Antiochus's accession, Media and Persis re volted under their governors, the brothers Molon and Alexander. The young king was in the hands of the bad minister Hermeias, and was induced to make an attack on Palestine instead of going in person to face the rebels. The attack on Palestine was a fiasco, and the generals sent against Molon and Alexander met with disaster. Only in Asia Minor, where the Seleucid cause was represented by the king's cousin, the able Achaeus, was its pres tige restored and the Pergamene power driven back to its earlier limits. In 221 Antiochus at last went east, and the rebellion of Molon and Alexander collapsed. The submission of Lesser Media, which had asserted its independence under Artabazanes, followed. Antiochus rid himself of Hermeias by assassination and returned to Syria (22o). Meanwhile Achaeus himself had revolted and as sumed the title of king in Asia Minor. Antiochus considered that he might leave Achaeus for the present and renew his attempt on Palestine. The campaigns of 219 and 218 carried the Seleucid arms almost to the confines of Egypt, but in 217 Ptolemy IV. defeated Antiochus at Raphia and compelled him to withdraw north of the Lebanon. In 216 Antiochus went north to deal with Achaeus, and had by 214 driven him into Sardis. Antiochus con trived to capture Achaeus (see POLYBIUS), but the citadel held out till 213.