The Ionic Revolt
Problems first started appearing in about 499 B.C. The main reason for the revolt was not due to any hatred against the Persians. It was to do with the fact that, due to be governed by tyrants, they were unable to develop into large city-states that had sprung up around Greece.
This an important fact that should again be emphasized. The Greeks were not revolting against the King of Persia, but against the tyrants who he had installed. The Persians were actually well known for tolerance against other cultures.
In order to rally together support for this revolt messengers were sent to mainland Greece. Sparta refused to help in any way, and it was left to Athens and Eretria to help the Ionic people.
With the revolt gaining momentum, tyrants in most of the Aeolian, Ionic and Dorian colonies were removed, and the revolt then turned its attention to the Persians themselves. Sardis, which was the old capital of the past Lydian empire was amazingly conquered and burnt to the ground.
This revolt however, was suppressed by Darius and the Persian army, who completely destroyed the Greek fleet at Lade and then followed up with the destruction of Milete in 494 B.C.
The Persians, realizing that their system of installing tyrants was the cause of this revolt, scrapped this idea and introduced a similar system of democracy that was in operation in mainland Greece. This did not help many of the Asian Greeks in the colonies, and many of them actually immigrated to Greece and other colonies in the west.