The Theban government has for the past three and a half years been in the hands of the small dictatorship, backed by a Spartan garrison in the Cadmeia.
Many of the previous leaders, including Pelopidas, have been driven into exile.
Pelopidas, who had fled to Athens, has taken the lead in a conspiracy to liberate Thebes.
His friend Epaminondas has remained in private life, but when Pelopidas, returning secretly from Athens with his party, surprises and kills their chief political opponents in 379 and, by arousing the Theban people, frightens the Spartan garrison into surrender, Epaminondas is said to have been one of those who led the popular uprising in Thebes.
The Thebans, who defeat two Spartan relief forces, are helped by Athens, though at first unofficially.