Battle of Marathon

In 490 BCE, a Persian invasion force landed at Marathon, about 25 miles from Athens. Despite being heavily outnumbered, the Athenian hoplites charged and routed the Persians in one of history's biggest upsets. Legend says a messenger ran the 26 miles to Athens to announce the victory and then died — which is why marathons are a thing. Herodotus documented the whole battle and the archaeological evidence at the burial mound checks out.