The two Persian Wars, the first lead by the Persian Emperor King Darius in 490 B.C. and then the second by his son Xerxes from 480 -479 B.C. are often considered to be a crucial turning point in western history. The empire once known as Persia is now made up of the modern day countries of Iran, Iraq, Turkey, and Afghanistan all eventually following the Islamic religion. Most of their neighbors in the region are also Islamic states, compared to our Christianity based systems. With what we now know of history, we can look at this time and see that the Greek victories over Persia were very important to Greece, their beliefs, the eastern Mediterranean and eventually western civilization as a whole.
The wars between Persia and Greece started over Greek settlements in Ionia. The Greeks living there were so overtaxed that they eventually rebelled against the local tyrants appointed by Darius.
The rebels sought and received a promise from Athens for help and received twenty warships to aid with their cause.1 Darius then decided to invade Greece because Athens aided the Ionians in their revolt and therefore Greece needed to be subdued to guarantee Persian security. After some initial gains against Athens the Persian army landed at Marathon which was just outside of Athens itself. The Athenians, with very few allies, faced the much larger Persian army. During the battle the outnumbered Athenian hoplites roundly defeated the Persians. This victory meant a lot to the Athenians; it gave them confidence in their ability as a military and paved the way for further democratic developments. As a punishment for Athens part in the Ionian revolt, had Persia defeated them, Darius was going to install Hippias as a tyrant over them.
1Mortimer Chambers and others, The Western Experience. 9 ed.