Under the Seleucid and Pergamene kingdoms

Immediately upon the death of Alexander, his quondam empire was broken up into individual kingdoms by his successors. One of these was the kingdom of Seleucus. Tralles and its vicinity became an important part of this kingdom in western Anatolia and, as its administrative center, the city began to be called Seleucei. In order to ensure the security of trade routes, King Antiochos I established the city of Antiochia, named after himself, at the eastern extremity of the Maeander valley.
As one consequence of the attempts of the Romans to spread their influence into Anatolia, the Seleucids were expelled from the Maeander valley under the treaty of Apamea in 188 B.C. and the region came under the control of the Kingdom of Pergamon, Rome’s ally.
Among the Hellenistic kingdoms in Anatolia, Pergamon was the most advanced in science, art, and civil engineering. After the death of KingEumenes II, he was succeeded by Attalos Ml who, though not entirely of sound mind, bequeathed his kingdom to Rome in his will after his death in 133 B.C. Aristonicus, the son of Eumenes II, rejected the validity of the bequest and assumed the throne himself. Despite his resistance to Rome however, he was taken prisoner three years later and put to death. In 129 B.C., the Pergamene kingdom — and with it, its territory in the Maeander valley — became the Roman province of Asia.
The kings of Pergamon were avid builders of public works and thus Tralles (Aydin) and its vicinity were developed substantially. Such famous works as the temple to Apollo in Didyma (Didim), the temple to Athena in Priene, and the temple to were all built during this period.