499 BC the Greek cities in Ionian (Minor Asia) got besieged of the Persians and asked help from Athens. The Persians spread out their territories from 547 BC till Thrace and Macedonia and granded a hiding-place for the tyrant Hippias, one more reason for Athens to intervene.

Athens troops pushed 498 BC forward till Sardes, but then near Ephesus they got defeated totally and pulled back to Athens. Miletus was still fighting till 494 BC. But then the Persians destructed it totally and the revolt stopped.

So like this started also the conflict between Athens and the Persians, which never forgot them for the support to the Ionian cities.