Athens Defeats the Persians at Marathon

In the late summer of 490 BCE, an Athenian citizen force stood arrayed across the coastal plain of Marathon to resist a Persian amphibious invasion. King Darius I of Persia had dispatched a punitive fleet across the Aegean Sea, commanded by Datis and Artaphernes, following Athenian and Eretrian intervention in the earlier Ionian Revolt. After besieging and destroying Eretria on the island of Euboea, the Persian expedition sailed south to Attica and came ashore in the bay of Marathon, guided by the deposed Athenian tyrant Hippias. Facing an existential threat, the Athenians mustered their heavy infantry and marched to block the inland exits from the coastal plain.

The defenders faced unfavorable numbers and severe strategic risk. Ancient authors record an Athenian contingent of roughly nine to ten thousand men, reinforced by a thousand hoplites sent from the allied town of Plataea. In contrast, while classical historians cited Persian strengths ranging from several hundred thousand, modern estimates place the Persian invasion force nearer to twenty-five thousand infantry and perhaps one thousand cavalry. Athens dispatched a courier named Pheidippides across more than two hundred kilometers to seek Spartan assistance, but the Spartans deferred their march until the full moon for religious reasons, a delay usually linked to the festival of the Carneia, leaving the Athenians and Plataeans to confront the invasion alone.