In the year 480 BC the Greek allies   faced invasion by the King of Persia,Xerxes,who commanded a huge army of about half a million men. When the Persian army marched into northern Greece,the Greek states,led by Athens and Sparta,were ill equipped to deal with the threat. The Persians were well supplied with food and weapons. Their army included infantry,cavalry,and a large navy. It seemed that they would easily defeat the Greeks. The Greek allies decided to send 10,000 men northwards to slow down the Persians,while the rest prepared to defend their homelands. A group of 300 best Spartan soldiers were chosen to lead the force going north,with Leonidas in command. Leonidas realised that the only hope of slowing the Persians would be to block the narrow passage of land at Thermopylae. The Pass of Thermopylae was the route between the mountains and the sea,and was so narrow that only a few men could get through at a time. When the Persian army arrived at Thermopylae,they found Leonidas' tiny army opposing them. The Persians attacked,but could not get through. They attacked again and again,but each time they were driven back by the Greeks,led by the fearless Spartans. Leonidas'plan worked well until a Greek traitor called Ephialtes went to Xerxes. He told the Persian king about a goat's path in the mountains that would take the Persian army past Thermopylae. When Leonidas saw the enemy crossing the mountains,he realised that he could no longer hold Thermopylae. He sent all the Greek soldiers except the 300 Spartans back to their homelands. The Spartans waited for the 500,000 Persians at the goat's path. Although hopelessly outnumbered,the Spartans fought bravely. They all died,but the other Greeks were able to get home to strengthen the defences. Compared with the Persian army,the Greek allies were very  _  .
powerful wise weak foolish