He inherited lasting tensions with
Ptolemaic Egypt and soon initiated the
Second Syrian War in alliance with
Antigonus II of the
Antigonid dynasty. The war was largely fought along the coasts of
Asia Minor and conflated with the constant intrigues of petty despots and restless city-states in Asia Minor. Antiochus II made some gains in Asia Minor and acquired direct access to Aegean Sea by capturing
Miletus and
Ephesus. During the war he assumed the title
Theos (
Greek: , "God"), being such to the Milesians in slaying the tyrant
Timarchus. At around the same time Antiochus II also made some attempt to get a footing in
Thrace which details are largely unknown and a mint in the city of
Byzantium briefly issued coins in his name. In the end the war did little to alter the general balance of power in the Eastern Mediterranean.
Coele-Syria in particular, the main disputed territory between the Seleucid empire and the Ptolemaic Kingdom, remained firmly in the hands of the Ptolemies. In 257 BC, the Ptolemaic
pharaoh Ptolemy II Philadelphus even invaded the Seleucid-held part of Syria, though the outcome of this invasion is unknown. In 253 BC, with his Antigonid allies knocked out of the war by rebellions, Antiochus II made peace with Ptolemy II. As part of the settlement, Antiochus II divorced
Laodice and married Ptolemy II's daughter
Berenice, with the understanding that any children born from their union would inherit the Seleucid throne. Laodice was well provided for in the divorce arrangement. Antiochus II gave her various land grants throughout Anatolia which are known through inscriptions; such as large estates in the
Hellespont, other properties near
Cyzicus,
Ilion and in
Caria. According to a royal record at
Sardis, her land titles were to be treated as in royal possession. Laodice remained a very powerful and political influential figure and continued numerous intrigues to become queen again. By 246 BC, possibly at the news of Ptolemy II's death, Antiochus II had left Berenice and their infant son Antiochus in
Antioch to live again with Laodice in Asia Minor. A succession struggle erupted almost immediately. Berenice initially had the advantage by holding Antioch but her son Antiochus was but an infant. Meanwhile, Laodice proclaimed her eldest son Seleucus as king
Seleucus II and moved in from Asia Minor, claiming that on his deathbed Antiochus II reversed his earlier decision and named Seleucus as his successor. ==Eastern affairs==