Battle of Artemisium
The naval Battle of Artemisium took place, according to tradition, on the same day as the Battle of Thermopylae on August 11, 480 BC, but it may have been a few days before or after. It was between an alliance of Greek city-states and the Persians in 480 BC.
The Greek force, according to Herodotus, consisted of 127 triremes from Athens and Plataea, 20 from Athens and Chalcis, 40 from Corinth, 20 from Megara, 18 from Aegina, 12 from Sicyon, 10 from Sparta, 8 from Epidaurus, 7 from Eretria, 5 from Troezen, 2 from Styra, and 2 from Ceos. There were also 9 other ships (penteconters, fifty-oared ships). In order to preserve the unity of the force, the Athenians, the most skilled of the Greeks in naval matters, allowed the fleet to be led by Eurybiades of Sparta. The Greek fleet planned to meet the Persians off of Artemisium on Euboea, and had probably been planning a battle for approximately the same date as Thermopylae.
The Persians at first met the Greeks off the coast of Thessaly, at Aphetae, close to Thermopylae, as the Athenian commander Themistocles attempted to delay the Persians while the island of Euboea was being evacuated. The Persians sent 200 ships around the south of Euboea, hoping to trap the Greeks in the channel, but a Persian defector warned the Greeks of this plan. A Greek squadron set out to meet them, so the Persians sent out some ships of their own to capture them. The Greek triremes surrounded these ships, and although they were outnumbered, were able to defeat them with the rams on their bows, and captured thirty Persian ships. The Persian fleet retreated for the night, and all 200 Persian ships still sailing around Euboea were destroyed in a sudden violent storm that same night. The next day 53 more Athenian ships arrived, and a Greek raid destroyed some Persian scout ships.
The following day (August 11 if the tradition of the simultaneous battles is to be believed), the Persians sailed towards the Greek fleet, forming a semi-circle in an attempt to trap them off Artemisium. Here the size of the Persian fleet worked against them, as they could not manoeuvre in the strait, and much of the fleet was destroyed by the Greeks. Five Greek ships were captured by the Egyptian contingent, while the Athenian Cleinias, the father of Alcibiades, single-handedly sank a large number of Persian ships. However, the Greek fleet also suffered heavy casualties, though not as heavy as the Persians.
The two sides withdrew once more, and the Greeks learned of the defeat of Leonidas at Thermopylae. Discouraged by their own losses in the battle and the retreat of the land armies, the Greeks began to retreat from Artemisium, heading south along the coast of Euboea. During the retreat, Themistocles left messages for the Ionian contingents of the Persian fleet, urging them to defect to their fellow Greeks. Meanwhile, the Persians sacked Artemisium. The Athenians under Themistocles went to Salamis Island, where their fellow citizens had fled after Xerxes I captured their city following his victory at Thermopylae. Themistocles would lead the fleet at the Battle of Salamis the next month.