The Battle of Artemisium, or Artemision is a series of naval engagements over three days during the second Persian invasion of Greece.

The battle takes place simultaneously with the more famous land battle at Thermopylae, in August or September 480 BCE, off the coast of Euboea and is fought between an alliance of Greek city-states, including Sparta, Athens, Corinth and others, and the Persian Empire of Xerxes I.The Persian invasion is a delayed response to the defeat of the first Persian invasion of Greece, which had been ended by the Athenian victory at the Battle of Marathon.

King Xerxes hs amassed a huge army and navy, and set out to conquer all of Greece.

The Athenian general Themistocles proposes that the Allied Greeks block the advance of the Persian army at the pass of Thermopylae and simultaneously block the Persian navy at the Straits of Artemisium.

An Allied naval force of 271 triremes is thus dispatched to await the arrival of the Persians.Approaching Artemisium towards the end of summer, the Persian navy is caught in a gale off the coast of Magnesia and loses around a third of their 1200 ships.

After arriving at Artemisium, the Persians send a detachment of 200 ships around the coast of Euboea in an attempt to trap the Greeks, but these are caught in another storm and shipwrecked.

The main action of the battle takes place after two days of smaller engagements.

The two sides fight all day, with roughly equal losses; however the smaller Allied fleet cannot afford the losses.After the engagement, the Allies receive news of the defeat of the Allied army at Thermopylae.

Since their strategy requires both Thermopylae and Artemisium to be held, and given their losses, the Allies decide to withdraw to Salamis.

The Persians overrun Boeotia and capture the now-evacuated Athens.

However, seeking a decisive victory over the Allied fleet, the Persians are later defeated at the Battle of Salamis in late 480 BCE.

Fearing being trapped in Europe, Xerxes withdraws with much of his army to Asia, leaving Mardonius to complete the conquest of Greece.

The following year, however, sees an Allied army decisively defeat the Persians at the Battle of Plataea, thereby ending the Persian invasion.