Near the present-day Manisa, at ancient Magnesia ad Sipylum, a battle was fought between Roman legions and the armies of Hannibal and the Seleucid Antiochus III. The year was 190 B.C. and the battle was called the Battle of Magnesia. This was one of the turning points of history, the start of a long period to follow of Roman power in Anatolia.
The Seleucids were driven beyond the Hallys River. Slightly more than a decade later, Hannibal, having found refuge with Prusias, King of Bithynia, commited suicide rather than submit to a demand by the Romans that he be surrendered to them. He was buried in Gebze. The Romans pushed on across Anatolia moving into territories controlled by Celts; Carthaginians, Greeks, Syrians, Parthians and, even, Egyptians. With the victory over the Seleucids, there was little to keep the Roman expansion in check. This movement had started with Emperor Trajan; before his time no Roman leader had felt the urge to conquer the world.
Among Rome's strongest allies in Anatolia were the kings of Pergamum and the Republic of Rhodes. After the victory over the Seleucids, Roman authority in the region was assured, Rome soon reduced the forces and consequent power of these two major allies. To take the position that Rhodes had commanded, the Romans established a huge commercial center at Delos. Here the slave traffic was renowned in antiquity. Pergamum, in turn, was also heavily restricted. In the wake of the Roman legions followed the officials to govern the acquired territories. Soon after, the businessmen arrived. With the Roman invasion in terms of officials and profit-seekers came, inevitably, encroachment upon civil liberties and ways of life of the indigenous peoples of Anatolia. They were restless and resentful. The power in the Pontus region of Anatolia, which ran from Samsun on the Black Sea to Batum, belonged to Mithridates VI. By taking advantage of the popular feeling, in the country and the internal troubles being experienced in Rome, Mithridates swept through the Roman occupied territories in 88 B.C. slaughtering the Romans and creating havoc in the prevailing order. He is said to have killed more than 80, 000 people in one day with the help of the people native to Anatolia. The situation turned against Mithridates when Roman reinforcements were brought into the area, then back to his favor after a while. It went on in this manner, with the Romans and Mithridates alternating the position of superiority in Anatolia.