Xerxes I portrayed on the Apadana Audience relief. Photo courtesy of Livius.org.
Xerxes I (son of Darius I) planned to invade Europe through Greece. He gathered an army of approximately a quarter of a million men and set off for Greece. The Spartans met Xerxes’ army at Thermopylae and fought valiantly against it although there were only 300 Spartan soldiers. In soldier-to-soldier combat the Spartans were superior soldiers and had superior weapons. In desperation, Xerxes ordered his soldiers to retreat and shoot with their bows and arrows. The remaining Spartan soldiers were annihilated in this way. Xerxes had lost 10,000 soldiers.
A simultaneous naval battle at Artemisium was tactically indecisive as large storms destroyed ships from both sides. The battle was stopped prematurely when the Greeks received news of the defeat at Thermopylae and retreated. The battle was a strategic victory for the Persians, giving them uncontested control of Artemisium and Aegean Sea.
Although Xerxes continued his march to Athens, the Greeks eventually defeated the Persians at the naval Battle of Salamis, which led to his rapid retreat.