Battle of Artemisium

The naval Battle of Artemesium took place at the same time as the Battle of Thermopylae, in 480 BC.
Approaching Artemisium towards the end of summer, the Persian navy was caught in a gale off the coast of Magnesia and lost around a third of their ~1,200 ships.
After arriving at Artemisium, the Persians sent a detachment of 200 ships around the coast of Euboea in an attempt to trap the Greeks, but these were caught in another storm and shipwrecked.
The main action of the battle took place after two days of smaller engagements. The two sides fought all day, with roughly equal losses; however the smaller Allied fleet could not afford the losses.
After the engagement, the Allies received news of the defeat of the Allied army at Thermopylae. Their strategy was to hold both Thermopylae and Artemisium. So, given their losses, the Allies decided to withdraw to Salamis. The Persians overran Boeotia and captured the now-evacuated Athens. However, seeking a decisive victory over the Allied fleet, the Persians were later defeated at the Battle of Salamis in late 480