The cape of Artemisium was the second - phase, if one could call it that, of the defensive position taken up by the Greeks to defend the mainland. The first phase, land - based, was at Thermopylae. The second phase, seaborne, would be at Artemisium.
"Pray to the winds; for the winds would do Greece good service"
The campaign did not start well for the Greeks.
The Persian fleet left Therma and almost at once, a small squadron of Persian ships spotted three Greek look - out vessels ( one from Troezen, one from Aegina and the third from Athens). Almost as soon as the three ships had been spotted, they fled.
The Persian ships made quick chase and ended up capturing the Troezenian and Aeginetan triremes, the Athenian trireme ran aground at the mouth of the river Peneus.
Herodotus (VII: 176) describes Artemisium:
"The barbarians at once pursued, and the Troezenian ship, which was commanded by Prexinus, fell into their hands. Hereupon the Persians took the handsomest of their men-at-arms, and drew him to the prow of the vessel, where they sacrificed him; for they thought the man would be a good omen to their cause, seeing that he was at once so beautiful, and likewise the first captive they had made. The man who was slain was called Leo; and it may be that the name he bore helped him to his fate in some measure.
The Aeginetan trireme, under its captain, Asonides, gave the Persians no little trouble, one of the men-at-arms, Pythes the son of Ischenoüs, distinguishing himself beyond all the others who fought on that day. After the ship was taken this man continued to resist, and did not cease until he fell quite covered with wounds. The Persians who served as men-at-arms in the squadron, finding that he was not dead, but still breathed, and being very anxious to save his life, since he had behaved so valiantly, dressed his wounds with myrrh, and bound them up with bandages of cotton. Then, when they were returned to their station, the displayed their prisoner admiringly to the whole host, and behaved towards him with much kindness; but all the rest of the ship´s crew were treated merely as slaves.
Thus did the Persians succeeding taking two of the vessels. The third, a trireme commanded by Phormus of Athens, took to flight and ran aground at the mouth of the river Peneus. The barbarians got possession of the bark, but not of the men. For the Athenians had no sooner run their vessel aground than they leapt out, and made their way through Thessaly back to Athens. When the Greeks stationed at Artemisium learnt what had happened by fire-signals form Sciathos, so terrified were they, that, quitting their anchorage-ground at Artemisium, and leaving scouts to watch the foe on the highlands of Euboea, they removed to Chalcis, intending to guard the Euripus."
On leaving Therma, the fleet sailed to the Magnesian territory, and occupied the strip of coast between the city of Casthanaea and Cape Sepias. The ships of the first row were moored to the land, while the remainder swung at anchor further off. The beach extended but a very little way, so that they had to anchor off the shore, row upon row, eight deep. In this manner they passed the night. But at dawn of day calm and stillness gave place to a raging sea, and a violent storm, which fell upon them with a strong gale from the east - a wind which the people in those parts call Hellespontias.
Such of them as perceived the wind rising, and were so moored as to allow of it, forestalled the tempest by dragging their ships up on the beach, and in this way saved both themselves and their vessels. But the ships which the storm caught out at sea were driven ashore, some of them near the place called Ipni, or "The Ovens," at the foot of Pelion; others on the strand itself; others again about Cape Sepias; while a portion were dashed to pieces near the cities of Meliboea and Casthanaea. There was no resisting the tempest.
The storm struck ...... it is said that the Persians lost a minimum 400 ships.
But what effect did the loss of so many ships have on the Persians? This was loss was so massive that the Persians , now fearing a Thessalian attack, proceeded to build a massive barricade aroung their station. The material used, the wood from the wrecked ships which could be found on the beachline.
The Greeks believed the the storm had been caused by Boreas, God of the north wind. The storm raged for three days. Herodotus tells us that the storm died down on the fourth day after enough sacrifices had been made to Thetis and Nereids. (I am inclined to believe that the storm died down by itself .)
The Greek scouts which had been left in the highlands of Euboea hurried to inform their comrades about the events of the storm. The Greeks immediately offered libations in Poseidon´s honour and then returned to Artemisium. The Persians, once the storm had died down, drew their ships to the sea and sailed once again along the coast of the mainland. On passing the extreme point of Magnesia, they sailed into the bay that runs up to Pagasae.