They knew that the Persians found the pass, because of Ephialtes, and stood for a last stand. In the end all the Greeks, including Leonidas, fell in battle but fought with fury and desperation; even when their spears broke they fought with their swords. The number of dead Persians isn't fully known.

So he sent many of the troops back to their cities as to spare their lives but kept those who stood my him like the Thespians, except the Thebans who were kept against their will. In the end only 1700 Greeks remained. That being the Spartans, Thebans, Thespians and the helots.

The Peloponnesians proposed that they should fall back to the Peloponnese and hold the Isthmus. In response the Spartan King Leonidas, who led the army, attempted to get reinforcements from the allied Greek states but the army was split on whether to retreat or not.

As funds were being raised Caesar maintained a friendly relationship with the pirates but warned them that he would have them crucified. So he did just that with the help of volunteers as a warning to others; as he was treated well he slit their throats to lessen their suffering.

Then he was sent to Aristagoras, his son-in-law, who was governing Miletus to start a revolt against the Persians. That would result in the burning of Sardis with the help of the Athenians and Eritrians until they were recaptured.