423 BC

By place

Persian empire

• Ochus, satrap of Hyrcania and son of Artaxerxes I and a Babylonian concubine, seizes the Persian throne from his half brother Secydianus, whom he has executed. The new king rules as Darius II.

  Greece

• The Athenian general, Laches, successfully moves in the Athenian Assembly for an armistice with Sparta to check the progress of Sparta's most effective general, Brasidas. However, the "Truce of Laches" has little impact on Brasidas and collapses within a year.
• Brasidas ignores the proposed year-long truce and proceeds to take Scione and Mende in the hope of reaching Athens and freeing Spartan prisoners. Athens sends reinforcements under Nicias who retakes Mende.

  By topic

Drama

• Aristophanes' play The Clouds is performed as is Sophocles' play Maidens of Trachi and The Putine, by Cratinus.