The Battle of Marathon is known as the first attempt of the Persian king Darius I. to conquer Greece. The battle took place in 490 before Christ and was fought between the Persian Empire and the alliance between Athens and Plataea.
Because Athens and Eretria had supported the revolt of the Greek cities in Asia Minor against the Persians, Darius I. ordered the military action in order to restore his authority.
Upon the news of the Persian landing in the Marathon plain, Athens decided to immediately advance against the enemy with the entire army.
The Greeks apparently walked the last 1200 meters till they reached the Persian front. The reason for that was that they wanted to undermine the dreaded hail of arrows from the enemy.
Therefore the Hoplites (soldiers of Ancient Greek city-states) would have increased their approach speed significantly, especially in the last 200 meters, supported by the fact that the weight of their body armor had been reduced significantly in the years before in favor of better mobility.
Many historians say that another reason for the Greek victory was the absence of the Persian cavalry on the battlefield. This could indicate that the Greeks began the attack after the horses had been loaded on the ships again. This gave the Greeks a better chance against the Persians because the heavy infantry of the Athenians and Plataians was superior to them in close combat.
The victory of Marathon though wasn’t a decisive battle as it was the reason for the big Persian invasion in 480/479 before Christ. But the battle of Marathon revealed that a victory over the Persian troops was possible and that Athens was capable of such an achievement without the help of Sparta.
-by Jason A.-
Sources:
https://www.welt.de/geschichte/article168559705/Wie-die-Griechen-die-persische-Weltmacht-demuetigten.html
https://www.ancient.eu/Persian_Wars/