The Persian king, Darius brought 20000-60000 soldiers to invade Greece.
We've killed so many, but there's too much of them! We have to EVACUATE!
The Spartans force the massive Persian soldiers up a narrow valley so they don't have to fight them all at once.
They're up here, men!
With diligence, the Athenian refugees are led to safety while the soldiers damaged the Persians and are forced to retreat.
Retreat! We've taken too much damage!
These are the last ones! FINISH THEM OFF!
After the war, Sparta and Athens made an alliance named the Delian League. Where Athens called the shots. Sparta did not like this so they declared war on each other, starting another gruesome war. It would take another 70 years for Sparta to finally beat Athens, but they were left vulnerable to the attacks of Macedonia.