Third Syrian WarSyria
Antiochus II's son Seleucus II Callinicus came to the throne around 246 BC. Seleucus II was soon dramatically defeated in the Third Syrian War against Ptolemy III of Egypt and then had to fight a civil war against his own brother Antiochus Hierax. Taking advantage of this distraction, Bactria and Parthia seceded from the empire. In Asia Minor too, the Seleucid dynasty seemed to be losing control: the Gauls had fully established themselves in Galatia, semi-independent semi-Hellenized kingdoms had sprung up in Bithynia, Pontus, and Cappadocia, and the city of Pergamum in the west was asserting its independence under the Attalid Dynasty. The Seleucid economy started to show the first signs of weakness, as Galatians gained independence and Pergamum took control of coastal cities in Anatolia. Consequently, they managed to partially block contact with the West.