351 BC

By place

Persian Empire

• Encouraged by a failed effort at invasion of Egypt by King Artaxerxes III, Phoenicia and Cyprus revolt against Persia.

  Greece

• Demosthenes tries to get the Athenians to cease depending on paid mercenaries and return to the old concept of a citizen army. He also delivers his First Philippic, warning Athenians of the folly of believing that Philip's ill health will save Athens from the Macedonians. In response, Athens' citizens votes for increased armaments.

  Roman Republic

• The Etruscans are badly defeated by the Romans and abandon their attacks on the city and sue for peace.
• First use of the heavy throwing spear, the pilum, in battle against the Gauls.
• Gaius Marcius Rutilus becomes the first Roman plebeian to be elected to the office of censor.