In 382 BC, the Spartans seized the Cadmea, the citadel of Thebes, whose increasing strength was a thorn in their side. This act costed them the rest of their credit as protectors of autonomy and led to the Boeotian War with the Thebans and their Athenian allies. In the course of this, in spring 377 BC, the Second Athenian Confederacy was established. This league represented a violation of the clauses of the Peace of Antalcidas. But it is possible that a majority of the Aegean islands and coastal states now saw Athens as a better advocate of the principle of autonomy, as a result of their support for the Thebans. The league treaty was explicitly concluded: