The Thirty Tyrants (404–403 BC) was an oligarchy installed by Spartans to run Athens following the Peloponnesian War.
The Thirty Tyrants were installed by the oligarchy who were controlled by Critias.
The Thirty Tyrants killed as many as 1,500 people in order to maintain power. Opponents to the Thirty Tyrants fled Athens but returned and defeated them in 403 BC at the battle at Piraeus. The Thirty Tyrants then fled, but were tracked down and killed within a few years.