In Assassin's Creed Odyssey, the Peloponnesian War begins in 431 BCE.
The game is set during the long conflict between Athens and Sparta, which historical sources generally date from 431 to 404 BCE. Its world includes mainland Greece and the Aegean islands, allowing the player to visit locations associated with both sides of the war. The campaign also incorporates real political leaders, philosophers, generals, and battles into its fictional family story.
Odyssey is set before the historical Assassin Brotherhood formally appears, so it does not center on Assassins in the same way as many other entries. Its protagonist can be Alexios or Kassandra, depending on the player's selection, while the mercenary system and branching choices create an interactive version of classical Greece. The war's starting date is sometimes confused with 404 BCE, the year of Sparta's victory and Athens' defeat.