To block the Persian advance, a small force of Greeks blocked the pass of Thermopylae, while an Athenian-dominated Allied navy engaged the Persian fleet in the nearby straits of Artemisium. In the resulting Battle of Thermopylae, the rearguard of the Greek force was annihilated, whilst in the Battle of Artemisium the Greeks had heavy losses and retreated after the loss at Thermopylae. This allowed the Persians to conquer Phocis, Boeotia, Attica, and Euboea. The Allies prepared to defend the Isthmus of Corinth while the fleet was withdrawn to nearby Salamis Island.