What happened at Thermopylae battle of Persian War

The southern Greeks sent a small land force to hold the pass tostall the Persian land advance in order to force them to try toturn the position by a naval outflanking move through the ArtemsionStrait nearby. The Greek fleet was waiting to pounce on the Persianfleet to eliminate its threat.

The sea battle went on for three days, but the Greeks lost and hadto try again (successfully) at the later battle of Salamis furthersouth.

The force holding the pass, its mission now invalidated, evacuatedthe position and retied back to their cities. The Spartan andThespian contingents selflessly stayed behind to cover thewithdrawal and were destroyed.

The Greeks, lead by 300 Spartas decided to meet a much, much, muchlarger invading Persian foce head on in the Thermopylae Pass. Thenarrow pass would only allow so many soldiers to fight so manysoldiers at a time, nullifying the Persian advantages. The battlewent on until all the 300 Spartans had been killed. The battle wasa Persian victory. However, as this was going on, the Greek navylost to the Persian navy in the Straits of Artemesion, so thePasswas abandoned.