The Athenian fleet at Salamis was a formidable force. But how did this tiny city state raise a force of some 200 triremes? It was largely due to the intelligence, fortitude and driving force of one man, Themistocles.
Themistocles, son of Neocles, was a new breed in Athenian politics. He led a faction that exiled its opponents and pushed a foreign policy that had definite emphasis on the Navy. In the 480's B.C. in the wake of the previous Persian attempt to conquer Greece (which was foiled at the battle of Marathon) Themistocles was the first to clearly understand the danger Persia posed to Greece and also understood that Athens had only one way to thwart it, build a navy.
He expended tremendous political capital (and treasure extracted from the Athenian silver mines) to build the fleet. The Athenians, aware of his contributions and recognizing his fore-sightedness, elected him the admiral of their navy when the Persian threat became imminent. Unfortunately, for Themistocles, he was not put in command of the combined Navies of Greece, which included ships from the Aegean and the Peloponnesus, from states including Sparta, Aegineta and Corinth. Since the Spartans had been elected to lead the struggle against Persia, even though they had a much smaller fleet, they provided the commander of the entire force, a man named Eurybiades.
Yet Eurybiades and Themistocles got on fairly well for rivals. Eurybiades was intelligent enough to understand that Themistocles was a genius when it came to politics as well as naval warfare. It would be the joint efforts of these two leaders that would eventually win the day for the Greeks at Salamis.