The war many thought was unwinnable was just claimed as a victory for Greece. The Persian war began when Greece decided to help Greek-speaking city-states in rebellion against Persia. Persia was NOT happy.
In 490 BCE, the ruler of Persia at the time, Darius the Great initiated an attack on the Greek mainland. Under the order of Miltiades, an experienced general who had battled against Persia before, Athens attacked without even waiting for reinforcements! Their army was only a fraction of the Persian army’s size, however surprisingly, the Athenians had won! The next battle happened 10 years later after Darius had passed his power down to his son, Xerxes. In 481 BCE, with an army of hundreds of thousands of men and a navy of 600 ships, Xerxes went on another expedition against Athens.
Xerxes demanded the immediate submit of Athens without resistance. Many listened to Xerxes and gave up. Athens and Sparta, however, did not listen. They were going to resist until the end.
Because of an Athenian politician, Themistocles, Athens had already began a navy project and had completed over 200 ships by the invasion. The first battle between the newly united Greeks and Persia was located at Thermopylae. Here, Spartan King Leonidas fought against Persia with his 300 Spartans for 3 days! Thousands of Persians were killed until the rest of the Greek resistance was destroyed. After the frightening loss, the remaining Greek fleet hurried to evacuate the citizens of Athens and other surrounding communities to nearby islands, most of them being on the island of Salamis. After a while, the Greeks decided to battle the Persians head-on. The naval battle of Salamis resulted in an astounding victory for Greece.
This forced Xerxes to leave to Persia. The ending of this battle led to citizens returning to Peloponnesus which was heavily fortified, ready for Persian attack. Months later, Sparta concluded Persia was not willing to fight Greece at the heavily protected area and had decided to fight them in open battle. At Platea, Greece demolished Persia, forcing them off Greek territory, which ended the war in Greece’s favor.