The Athenian victory over Persia at marathon in 490 BCE was the first defeat for the Persians. Fortunately for the Athenians the Persian cavalry could not be used on the swampy ground. The Athenian military leader was Miltiades. His helmet which has his name inscribed on it can be seen in a museum in Greece.
(The Great Courses – The Long Shadow of the Ancient Greek World)
Amazing!