Following Athens' defeat in the Peloponnesian War, a narrow oligarchic government was imposed on the city by Lysander and the victorious Spartans. This government, which came to be known as the Thirty Tyrants as a result of its brutal actions, exiled or drove away a number of citizens. Many of these gathered at Thebes, where they received support and assistance from the anti-Spartan government of Ismenias. Late in 404 BC, 70 of these exiles, commanded by Thrasybulus, crossed the border into Attica and occupied the strong point of Phyle on Mount Parnes.