However, before her brother Ptolemy III, the king of Egypt, was able to land and support her son's claims, she was murdered by partisans of Seleucus II and Queen Laodice.

Ptolemy III invaded the Seleucid Empire and landing at Seleucia Pieria, accepted the surrender of Syria and Cilicia and marched victoriously to the Tigris or beyond (although he did not reach as far as Babylon).

[4] Ptolemy remained in Syria during the winter of 246-245 BC, while Seleucus sent an expedition by sea to retake the area, only to have it wrecked by storms; not the last time he was to be defeated by bad luck.

Ptolemy III returned to Egypt in 245 BC, reputedly taking with him 40,000 talents of gold and the statues of Egyptian gods which had been looted centuries before by the Persians.

Seleucus crossed into Babylonia and Mesopotamia first, receiving the loyalty of the empire's Eastern regions and then marched into Syria where he recovered Antioch by 244 BC.

In the Aegean, the Ptolemaic armies were able to seize control of Ephesus, as well as Ainos and Maroneia in Thrace, and several cities on the Asian side of the Hellespont.

However, before Seleucus was able to turn his attention eastwards, by 238 BC, Andragoras had been killed by Arsaces I, a chieftain of the nomadic Parni, based in the city of Nissa (modern day Nisa, Turkmenistan).

After the defeat at Ancyra, the Seleucid garrisons of the region were further weakened and this allowed the Parthians under Arsaces the opportunity to seize more territory, including the city of Hekatompylos, which became their new capital around 237 BC.

In short order, Attalus defeated the Galatians, Antiochus Hierax and finally an attempt by Seleucus II to reclaim his control of Asia Minor.

Seleucus by this time had his hands full dealing with rebellion in Antioch instigated by his aunt, Queen Stratonice, who had previously been married to King Demetrius II of Macedon.