16. Great campaign of Antiochus in the upper provinces, in consequence of the seizure of Media by Arsaces III.--Hostilities ended in a compact, by which Antiochus agreed formerly to cede Parthia and Hyrcania; Arsaces, on his side, pledging himself to furnish assistance against Bactria.--But the war with Bactria was also followed by a peace, leaving the king, Euthydemus, in possession of his crown and dominions.--The expedition now undertaken by Antiochus, in company with Demetrius of Bactriana, against India, extended, probably far up the country, and was attended with important consequences to Bactriana. (See below, history of Bactria, book iv. per. iii. Dist. Kingdoms iv. parag. 5.) The result of these great expeditions was the establishment of the supremacy of the Seleucidae in Upper Asia; those countries excepted which had been formally resigned. On his return through Arachotus and Carmania, where he wintered, he likewise undertook a naval expedition on the Persian gulf: here Gerrha, in possession of its freedom, appears a flourishing place of trade. 17. Resumption of the plan against Egypt, after the death of Ptolemy Philopator; and alliance with Philip of Macedonia, then carrying on war in Asia. Antiochus, it is true, attained his end in the expulsion of the Ptolemies from their possessions in Syria, Coele-Syria, and Phoenicia; but then, his success brought him in contact with Rome, an event of decisive importance to himself and his successors. 18. Growth of the disputes between the king and Rome, proceeding from the conquest of the major part of Asia Minor and the Thracian Chersonesus; meanwhile Hannibal had taken refuge at the Syrian court, and the probability daily increased of a great league being formed against Rome, although that power, after conquering Carthage, 201, and Macedonia, 197, had succeeded in winning over Greece even, by the magic spell of _freedom_. But Antiochus ruined all: instead of following Hannibal's advice, and attacking the Romans on their own ground, he stood on the defensive, and suffered himself to be invaded by them in Asia. His defeat at Magnesia near Mount Sipylus compelled him to accede to such conditions as Rome chose to dictate, and the power of the Syrian empire was for ever broken. For the history of this war, see below in the Roman history. Book v. per. ii. parag. 10, 11.