Son of Seleucus Kallinikos; succeeded to the throne of Syria in 222 BC; put to death his general, Hermeas, and then led an army against Egypt. Theodotus surrendered to him Tyre, Ptolemais and his naval fleet. Rhodes and Cyzicus, as well as Byzantium and Aetolia, desired peace, but Antiochus declined to accept their terms. He renewed the war, but was defeated at Raphia in 217, and was obliged to give up Phoenicia and Coelesyria; Seleucia, however, he retained. He undertook to bring under his sway again all the territory of the Far East. His expedition against Bactria and Parthia gained for him the surname of "The Great." In 209 he carried away the treasure of the goddess Aine in Ecbatana, defeated the Parthians, and in 208 marched against the Bactrians. Later he made a treaty with an Indian rajah, and then returned to the West by way of Arachosia and Carmania, forcing the Gerraean Arabs to furnish him with frankincense, myrrh and silver. Then he took Ephesus, which he made his headquarters. In 196 he had crossed the Hellespont and rebuilt Lysimachia. Hannibal visited Antiochus in Ephesus the next year and became one of the king’s advisers. He sought the friendship also of Eumenes of Pergamum, but without success.
Rome now requested the king not to interfere in Europe, or to recognize the right of the Romans to protect the Greeks in Asia. A war broke out in 192, and Antiochus was persuaded to come to Greece. The Aetolians elected him their general, who asked the Acheans to remain neutral. But the patriotic Philopoemen decided that an alliance with Rome was to be preferred. Antiochus first captured Calchis; then succeeded in gaining a footing in Boeotia, and later made an effort to get possession of Thessaly, but retired on the approach of the Macedonian army. In 191 the Romans made a formal declaration of war on Antiochus, who, being at that time in Acarnania, returned to Calchis, and finally sailed back to Ephesus. The Romans regained possession of Boeotia, Euboea and Sestus; but Polyxenidas defeated the Roman fleet near Samos, which island, together with Cyme and Phocaea, fell into the hands of Antiochus. The victorious Polyxenidas, however, soon sustained a crushing defeat at the hands of the Romans, and Antiochus abandoned Lysimachia, leaving an open road to Asia to the Romans. He was finally defeated at Magnesia and sent word to Scipio, who was at Sardis, that he was willing to make peace; but Scipio ordered him to send envoys to Rome. A decision was reached in 189; the Asiatic monarch was obliged to renounce everything on the Roman side of the Taurus; give up all his ships of war but ten and pay 15,000 talents to Rome, and 500 to Eumenes. Antiochus marched against the revolted Armenians in 187. In order to replenish his exhausted treasury, he attempted to plunder a temple and both he and his soldiers were slain by the Elymeans.
LITERATURE. Polyb. v.40.21; Livy xxxi.14; xxxiii. 19 ff; Josephus, Ant, XII; Heyden, Res ab Ant; Babelon, Rois de Syrie, 77-86;