The defeat at Coronea, however, triggered a more dangerous disturbance, in which Euboea and Megara revolted. Pericles crossed over to Euboea with his troops to quash the rebellion there, but was forced to return when the Spartan army invaded Attica. Through negotiation and possibly bribery, Pericles persuaded the Spartan king Pleistoanax to lead his army home. Back in Sparta, Pleistoanax would later be prosecuted for failing to press his advantage, and fined so heavily that he was forced to flee into exile, unable to pay. With the Spartan threat removed, Pericles crossed back to Euboea with 50 ships and 5,000 soldiers, crushing all opposition. He then inflicted a harsh punishment on the landowners of Chalcis, who lost their properties. The residents of Istiaia, who had butchered the crew of an Athenian trireme, were uprooted and replaced by 2,000 Athenian settlers. The arrangement between Sparta and Athens was ratified by the "Thirty Years' Peace" (winter of 446–445 BC). According to this treaty, Megara was returned to the Peloponnesian League, Troezen and Achaea became independent, Aegina was to be a tributary to Athens but autonomous, and disputes were to be settled by arbitration. Each party agreed to respect the alliances of the other.