The oldest son of Seleucus II proved not to be the "savior" that his official royal epithet advertised. Nor did he live up to his popular byname: "Thunder" [keraunos]. For he not only failed to reclaim western Asia Minor from his cousin, Attalus of Pergamum, but was assassinated in his second attempt, less than two years after his enthronement. Had his younger brother Antiochus III not reversed the family fortunes, his death might have brought the Seleucid dynasty to an end.

References: Josephus, Antiquities 12.223, 234.
                  Appian, Roman History: Syrian Wars 11.66.
                  Polybius, Histories 4.48.

Other resources on line:

• Seleucus III Keraunos - Jona Lendering lists biographical data & key events [Livius: Articles in Ancient History].

• Seleucus III Chronicle - translation of cuneiform tablet documenting Seleucus' support of celebrations for the traditional Babylonian New Year [on Livius: Articles in Ancient History].

• Seleucus III Ceraunus - entry in Wikipedia's web.

Youthful image of Seleucus III graces the face of a silver tetradrachma minted at Antioch in 226 BCE. The reverse bears the inscription Basileos Seleukou ["of king Seleucus"] flanking the nude figure of Apollo, with bow & arrow, seated on the omphallos at Delphi ["navel" of the Hellenic world].