He inherited a state of war with Ptolemaic Egypt, the "Second Syrian War", which was fought along the coasts of Asia Minor, and the constant intrigues of petty despots and restless city-states in Asia Minor. Antiochus also made some attempt to get a footing in Thrace. During the war he was given the title Theos, being such to the Milesians in slaying the tyrant Timarchus. During the time Antiochus was occupied with the war against Egypt, Andragoras, his satrap in Parthia, proclaimed independence. According to Justin's epitome of Pompeius Trogus, in Bactria, his satrap Diodotus also revolted in 255 BC, and founded the Greco-Bactrian Kingdom, which would further expand in India in 180 BC to form the Indo-Greek Kingdom. In 253 BC, in the aftermath of the Second Syrian War, Antiochus II made peace with the pharaohPtolemy II Philadelphus. He divorced Laodice and married Ptolemy II's daughter Berenice, with the understanding that any children born from their union would inherit the Seleucid throne. Although no longer queen, Laodice was still a very powerful and political influential figure. Antiochus gave Laodice various land grants throughout Anatolia which are known through inscriptions; she owned a large estate in the Hellespont, other properties near Cyzicus, Ilion and in Caria. In a royal record at Sardis mentions her land titles were to be kept as royal land in disposal in grants or sales. During her stay in Ephesus, Laodice continued numerous intrigues to become queen again. By 246 BC Antiochus had left Berenice and their infant son Antiochus, in Antioch to live again with Laodice I in Asia Minor. Laodice took the occasion to poison Antiochus while her partisans at Antioch murdered Berenice and their infant son. Antiochus was buried in the Belevi Mausoleum. Laodice I then proclaimed Seleucus II as King. With his cousin-wife Laodice I, Antiochus had two sons: Seleucus II Callinicus, Antiochus Hierax and three daughters: Apama, Stratonice of Cappadocia and Laodice.
Relations with India
An uncertain Antiochus is mentioned in the Edicts of Ashoka, as one of the recipients of the Indian Emperor Ashoka's Buddhist proselytism: Ashoka also claims that he encouraged the development of herbal medicine, for men and animals, in the territories of the Hellenistic kings: Alternatively, the Greek king mentioned in the Edict of Ashoka could also be Antiochus's father, Antiochus I Soter, who arguably had more proximity with the East.