This battle was important because it decided the victor in the Greeks vs. Persia War. The Greek side was victorious due to their strategist, Themistocles, and taking advantage of the environment. This battle placed Athens in charge of the Delian League and prevented Persia from taking over Greece. The troop ratio was 2:1, favoring the Persians.
Events which led to the battle of Salamis: Persia is gaining ground on Greece, surpassing Spartan blockade, and eventually reached Athens, which was deserted. The Athenian navy was docked at the straits of Salim, where the battle took place.