Although its specter had hovered over western Anatolia since the Peace of Apamea in 188, Rome had made no tangible moves to incorporate the territory into its empire. This was a reflection of the fact that there was still substantial opposition in the Senate to Roman expansion into Asia. The issue was brought to a head, however, when the king of Pergamum, Attalus III (138–133), faced by social unrest and the lack of an heir, decided to minimize the risks of political and social upheaval after his death by making Rome his legal heir.
When Attalus died in 133 the Senate, without great enthusiasm, decided to accept the legacy and take over most of the rich country. This promptly led to a revolt by Aristonicus, the illegitimate son of Attalus’ predecessor. A Roman army under the consul Crassus was sent to suppress the revolt in 131, but met with defeat. A second attempt the following year under the consul Perperna proved more successful, with Aristonicus being taken captive. Nonetheless, the conflict continued for another year before a third commander, Aquilius, finally brought it to an end. The principal part of the territory of Pergamum was annexed to Rome as the new province of Asia. Some of the less fertile and therefore less valuable districts of the country such as Phrygia and Lycaonia, even though of strategic significance, were turned over to the kings of Pontus and Cappadocia, respectively, as rewards for their loyalty to Rome in the recent conflict. Although Rome had no expansionist objectives in Asia at the time, as evidenced by its voluntary cession of territory to some of the local rulers, the acquisition of Pergamum necessarily increased the direct stake of Rome in the turbulent region and inevitably involved it in political developments there.