239 BC

By place

Carthage

• Concerned that Hamilcar Barca's leniency in pardoning those who he has captured who have participated in the Mercenary War will encourage others to defect, Mathos and Spendius order the mutilation and execution of "about seven hundred" Carthaginian prisoners, including Gesco. With the mercenaries jointly guilty of these atrocities, defectors dare not face Carthaginian justice under Hamilcar.
• Carthage is besieged by the mercenary armies, while the city of Utica revolts and attempts to secede from Carthage. Carthage appeals to Hiero II of Syracuse and to Rome for aid against the mercenaries. However, the mercenary leaders reject the efforts of Roman mediators.
• Sardinia revolts against Carthage and Rome takes the opportunity to annex the island.

  Greece

• Antigonus II, King of Macedonia, dies and is succeeded by his son, Demetrius II.
• With Aetolia now as its ally, the Achaean League under the command of Aratus of Sicyon repeatedly attacks Athens and Argos.

  Seleucid Empire

• Seleucus II's brother Antiochus Hierax, who is governor of Seleucid Anatolia, sends an army into Syria ostensibly to assist Seleucus but actually to seize the rest of the empire. After achieving peace with Egypt, Seleucus II promptly invades Anatolia and begins the "War of the Brothers".

  Persia

• Diodotus of Bactria defeats an army of Parthians. He dies shortly thereafter and is succeeded by his son Diodotus II.

  Korea

• Haemosu, who is a descendant of the people of the empire of Gojoseon, establishes the ancient kingdom of Bukbuyeo in modern-day Jilin, northeast China.