By approximately 500 B.C. Persia controlled nearly the entire world as they knew it. The Persian Empire sprawled over all of Asia Minor, Lydia, Judah, Mesopotamia, and Egypt. When they turned their eyes westward towards Greece and the rest of Europe, they were justified in believing nothing could stand in their way. It was King Darius who proudly led his army over the mainland to the Greek peninsula. It would be his son Xerxes who retreated home some twenty years later.
The first eighteen years or so of the Greco-Persian Wars bore witness to the Persian army being gloriously triumphant again and again. The overwhelming Athenian victory at the Battle of Marathon was merely a distraction to the Persian forces as they murdered and razed their way through the Greek countryside. King Darius himself watched from a nearby hillside, as was his nation's tradition, as his forces killed Spartan general Leonidas and 300 strong soldiers in the Battle of Thermopylae. As a direct result of that victory, Spartan forces amassed and waited with allies at the Isthmus of Corinth. King Darius was called away to see to a riot in the eastern reaches of his kingdom, where he was killed. His son Xerxes ascended to the throne, and immediately set forth the entire Persian fleet for Greece to show the strength of the Persian army to quell any future uprisings against the throne.
The year was 480 B.C. and the Athenians, the most respected Greek city-state citizens, were in disarray. Their city was burning around them, families were torn apart by war, and the city underwent a huge exodus to the island of Salamis, where the Athenians fretfully put their trust in their navy to save them.
The Athenian army consisted of 350 Trieris vessels and 85,000 men. Athenian Themistocles was in charge of tactical planning and staging, while a Spartan General (Eurybiades) carried out orders and was in charge of the Greek army. They thus entrenched themselves in the Strait of Salamis (between the lands of Salamis and Attica) with only 50 ships protecting the northern opening of the strait and awaited the Persian army who were rapidly approaching from the south. A commendable illustration of the Greek defense can be found at the Salamina website quoted below.
Xerxes had led a fleet of 1200 vessels and 300,000 men from his mainland. However, fierce autumn storms had damaged several ships and forced others to turn back. By the time the fleet was on its final approach, Xerxes and Persian General Ahemeno had 700 vessels, having lost nearly half of their fleet. The Persians, of course, still had a huge advantage in numbers.
It was in the late autumn of 480 B.C. that the Athenian navy chased the much larger Persian fleet away from their homeland. The smaller, more maneuverable Greek ships used hit and run tactics to ram the Persian ships, and then employed their far superior knowledge of the strait to ground and sink over 200 ships in a single day. Xerxes sadly pulled his fleet out of the strait, pausing only once to land several thousand soldiers on the mainland before returning home. While Persian soldiers would remain in Greek lands for several more years, they never regained their sense of fear in the Greeks, as the Spartan force from Corinth swept much of former Greek lands clean in the years following the Battle of Salamis. Persia would not win many more major battles in the Greco-Persian Wars, and Greece retained their lands until finally succumbing to the Roman Empire centuries later.