Herodotus, Marathon
On the Athenian charge at Marathon
What was going on: Herodotus is describing the battle of Marathon. The Athenians, few and with no cavalry or archers, charged the Persians at a run, and the Persians thought them crazy. The Athenians and Plataeans then won on both wings and chased the Persians to their ships.
They were the first Greeks we know of to charge the enemy at a run, and the first to face the Medes without panicking at their name.
These are the first Hellenes whom we know of to use running against the enemy. They are also the first to endure looking at Median dress and men wearing it, for up until then just hearing the name of the Medes caused the Hellenes to panic.