The Ionian rebellion brought in support from mainland Greekcity-states Eretria and Athens. After suppressing the revolt,Persia sent an expedition to capture those two city-states and putthem under control of local tyrants to stop them causing troublewithin the Persian Empire. This expedition was defeated, so thePersians decided that the only way to end Greek revolts was tobring all the mainland city-states under a Persian governor. Theymounted a full-scale invasion by land and sea.The southern Greek cities were thus under threat of a seainvasion, and had to keep their armies at home to protect theircities. They decided that their solution was to destroy the Persiannavy, so they could then bring their armies out to unite and defeatthe Persian army. They set up a blocking force at the pass ofThermopylae to force the Persians to turn the position by sea, andthe Greek navies were waiting in the nearby strait of Artemesion topounce on the Persian fleet.Unfortunately for the Greeks, their fleet lost the sea battle,and with the blocking force at Thermopylae of no further use, itwas withdrawn. The Spartan and Thespian elements of that forceremained in place to cover the withdrawal, and were lost.The Greeks tried again at Salamis and succeeded in destroyingthe Persian fleet, hen were able to assemble their armies thefollowing year at Plataea, and won, so the invasion wasdefeated.