Darius II (reigned 423-405 BC) consolidated Persia’s western conquests in the Aegean and across the Hellespont into Thrace. However in 598 BC the Greek cities of Ionia, supported in part by Athens, revolted. It took the Persians four years to crush the rebellion although an attack against mainland Greece was repulsed at Marathon in 490 BC. The attempt to secure the western provinces continued under Xerxes (reigned 486-465 BC) who tried to force the mainland Greeks to acknowledge Persian power.

Some Greek states (Thebes and Thessaly) did side with the Persians but Athens and Sparta refused. Xerxes led his sea and land forces against Greece in 480 BC, defeating the Spartans at the battle of Thermopylae and sacking Athens. However the Greeks won an important victory against the Persian navy in the straits of Salamis in 479 BC. It is possible that at this point a serious revolt broke out in the strategically crucial province of Babylonia. Xerxes rapidly departed Greece and successfully crushed the Babylonian rebellion. However, the Persian army left behind in Greece was defeated at the battle of Plataea in 479 BC. To pursue the war with Persia, Athens established the Delian League of states and successfully reduced Persian influence in the Aegean and the coast of Asia Minor.