The Ionian Revolt was triggered by the dissatisfaction of the Greek cities of Asia Minor with the tyrants appointed by Persia to rule them. In 499 BC, the then-tyrant of Miletus, Aristagoras, launched a joint expedition with the Persian satrap Artaphernes to conquer Naxos, in an attempt to bolster his position in Miletus. The mission was a debacle, and sensing his imminent removal as tyrant, Aristagoras chose to incite the whole of Ionia into rebellion against the Persian king Darius the Great. Initially, in 498 BC, the Ionians went on the offensive, supported by troops from Athens and Eretria, capturing Sardis, before suffering defeat at the Battle of Ephesus. The revolt then spread to Caria and Cyprus. Three years of Persian campaigning across Asia Minor followed, with no decisive effect. By 494 BC the Persian army and navy had regrouped, and made straight for the epicentre of the rebellion at Miletus.