The struggle was serious. There were no Roman troops in Asia; the Asiatic free cities and the contingents of the client-princes of Bithynia, Paphlagonia, Cappadocia, Pontus, Armenia, could not withstand the pretender; he penetrated by force of arms into Colophon, Samos, and Myndus, and already ruled over almost all his father's kingdom, when at the close of 623 a Roman army landed in Asia. Its commander, the consul and pontifex maximus Publius Licinius Crassus Mucianus, one of the wealthiest and at the same time one of the most cultivated men in Rome, equally distinguished as an orator and as a jurist, was about to besiege the pretender in Leucae, but during his preparations for that purpose allowed himself to be surprised and defeated by his too-much-underrated opponent, and was made a prisoner in person by a Thracian band. But he did not allow such an enemy the triumph of exhibiting the Roman commander-in-chief as a captive; he provoked the barbarians, who had captured him without knowing who he was, to put him to death (beginning of 624), and the consular was only recognised when a corpse. With him, as it would seem, fell Ariarathes king of Cappadocia. But not long after this victory Aristonicus was attacked by Marcus Perpenna, the successor of Crassus; his army was dispersed, he himself was besieged and taken prisoner in Stratonicea, and was soon afterwards executed in Rome.

The subjugation of the last towns that still offered resistance and the definitive regulation of the country were committed, after the sudden death of Perpenna, to Manius Aquillius (625). The same policy was followed as in the case of the Carthaginian territory. The eastern portion of the kingdom of the Attalids was assigned to the client kings, so as to release the Romans from the protection of the frontier and thereby from the necessity of maintaining a standing force in Asia; Telmissus[34] went to the Lycian confederacy; the European possessions in Thrace were annexed to the province of Macedonia; the rest of the territory was organized as a new Roman province, which like that of Carthage was, not without design, designated by the name of the continent in which it lay. The land was released from the taxes which had been paid to Pergamus; and it was treated with the same moderation as Hellas and Macedonia. Thus the most considerable state in Asia Minor became a Roman province.

The numerous other small states and cities of western Asia - the kingdom of Bithynia, the Paphlagonian and Gallic principalities, the Lycian and Pamphylian confederacies, the free cities of Cyzicus and Rhodes - continued in their former circumscribed relations. Beyond the Halys Cappadocia - after king Ariarathes V Philopator (591-624) had, chiefly by the aid of the Attalids, held his ground against his brother and rival Holophernes who was supported by Syria - followed substantially the Pergamene policy, as respected both absolute devotion to Rome and the tendency to adopt Hellenic culture. He was the means of introducing that culture into the hitherto almost barbarous Cappadocia, and along with it its extravagancies also, such as the worship of Bacchus and the dissolute practices of the bands of wandering actors - the "artists" as they were called. In reward for the fidelity to Rome, which had cost this prince his life in the struggle with the Pergamene pretender, his youthful heir Ariarathes VI was not only protected by the Romans against the usurpation attempted by the king of Pontus, but received also the south-eastern part of the kingdom of the Attalids, Lycaonia, along with the district bordering on it to the eastward reckoned in earlier times as part of Cilicia.

In the remote north-east of Asia Minor "Cappadocia on the sea", or more briefly the "sea-state", Pontus, increased in extent and importance. Not long after the battle of Magnesia king Pharnaces I had extended his dominion far beyond the Halys to Tius on the frontier of Bithynia, and in particular had possessed himself of the rich Sinope, which was converted from a Greek free city into the residence of the kings of Pontus. It is true that the neighbouring states endangered by these encroachments, with king Eumenes II at their head, had on that account waged war against him (571-575), and under Roman mediation had exacted from him a promise to evacuate Galatia and Paphlagonia; but the course of events shows that Pharnaces as well as his successor Mithradates V. Euergetes (598?-634), faithful allies of Rome in the third Punic war as well as in the struggle with Aristonicus, not only remained in possession beyond the Halys, but also in substance retained the protectorate over the Paphlagonian and Galatian dynasts. It is only on this hypothesis that we can explain how Mithradates, ostensibly for his brave deeds in the war against Aristonicus, but in reality for considerable sums paid to the Roman general, could receive Great Phrygia from the latter after the dissolution of the Attalid kingdom. How far on the other hand the kingdom of Pontus about this time extended in the direction of the Caucasus and the sources of the Euphrates, cannot be precisely determined; but it seems to have embraced the western part of Armenia about Enderes and Divirigi, or what was called Lesser Armenia, as a dependent satrapy, while the Greater Armenia and Sophene formed distinct and independent kingdoms.

While in the peninsula of Asia Minor Rome thus substantially conducted the government and, although much was done without or in opposition to her wishes, yet determined on the whole the state of possession, the wide tracts on the other hand beyond the Taurus and the Upper Euphrates as far down as the valley of the Nile continued to be mainly left to themselves. No doubt the principle which formed the basis of the regulation of Oriental affairs in 565, viz. That the Halys should form the eastern boundary of the Roman client-states[35], was not adhered to by the senate and was in its very nature untenable.

The political horizon is a self-deception as well as the physical; if the state of Syria had the number of ships of war and war-elephants allowed to it prescribed in the treaty of peace[36], and if the Syrian army at the bidding of the Roman senate evacuated Egypt when half-won[37], these things implied a complete recognition of hegemony and of clientship. Accordingly the disputes as to the throne in Syria and in Egypt were referred for settlement to the Roman government. In the former after the death of Antiochus Epiphanes (590) Demetrius afterwards named Soter, the son of Seleucus IV, living as a hostage at Rome, and Antiochus Eupator, a minor, the son of the last king Antiochus Epiphanes, contended for the crown; in the latter Ptolemy Philometor (573-608), the elder of the two brothers who had reigned jointly since 584, had been driven from the country (590) by the younger Ptolemy Euergetes II or the Fat (d. 637), and had appeared in person at Rome to procure his restoration.

Both affairs were arranged by the senate entirely through diplomatic agency, and substantially in accordance with Roman advantage. In Syria Demetrius, who had the better title, was set aside, and Antiochus Eupator was recognized as king; while the guardianship of the royal boy was entrusted by the senate to the Roman senator Gnaeus Octavius, who, as was to be expected, governed thoroughly in the interest of Rome, reduced the war-marine and the army of elephants agreeably to the treaty of 565, and was in the fair way of completing the military ruin of the country. In Egypt not only was the restoration of Philometor accomplished, but - partly in order to put an end to the quarrel between the brothers, partly in order to weaken the still considerable power of Egypt - Cyrene was separated from that kingdom and assigned as a provision for Euergetes. "The Romans make kings of those whom they wish", a Jew wrote not long after this, "and those whom they do not wish they chase away from land and people". But this was the last occasion - for a long time - on which the Roman senate came forward in the affairs of the east with that ability and energy, which it had uniformly displayed in the complications with Philip, Antiochus, and Perseus. Though the internal decline of the government was late in affecting the treatment of foreign affairs, yet it did affect them at length. The government became unsteady and vacillating; they allowed the reins which they had just grasped to slacken and almost to slip from their hands. The guardian-regent of Syria was murdered at Laodicea; the rejected pretender Demetrius escaped from Rome and, setting aside the youthful prince, seized the government of his ancestral kingdom under the bold pretext that the Roman senate had fully empowered him to do so (592). Soon afterwards war broke out between the kings of Egypt and Cyrene respecting the possession of the island of Cyprus, which the senate had assigned first to the elder, then to the younger; and in opposition to the most recent Roman decision it finally remained with Egypt. Thus the Roman government, in the plenitude of its power and during the most profound inward and outward peace at home, had its decrees derided by the impotent kings of the east; its name was misused, its ward and its commissioner were murdered. Seventy years before, when the Illyrians had in a similar way laid hands on Roman envoys, the senate of that day had erected a monument to the victim in the market-place, and had with an army and fleet called the murderers to account. The senate of this period likewise ordered a monument to be raised to Gnaeus Octavius, as ancestral custom prescribed; but instead of embarking troops for Syria they recognized Demetrius as king of the land. They were forsooth now so powerful, that it seemed superfluous to guard their own honour. In like manner not only was Cyprus retained by Egypt in spite of the decree of the senate to the contrary, but, when after the death of Philometor (608) Euergetes succeeded him and so reunited the divided kingdom, the senate allowed this also to take place without opposition.