Aristagoras, the Tyrant of Miletus was on an expedition to conquer the island of Naxos with Persian support, but that was a failure. Before he could be dismissed, Arisagoras encouraged Ionia to rebel against the Persians. This led to the Ionian Revolt. Aristagoras got support from Athens and Eretria, and together they burnt the Persian regional capital city, Sardis. The Persian king, now Darius the Great, vowed revenge.