 Arriving at the Isthmus of Corinth, the Thebans found it heavily guarded by the Spartans and Athenians (along with the Corinthians, Megarans and Pellenians).Epaminondas decided to attack the weakest spot, guarded by the Lacedaemonians; in a dawn attack he forced his way through the Spartan position, and joined his Peloponnesian allies.The Thebans thus won an easy victory and crossed the Isthmus.