The Spartans (documentary) the Spartan constitution into the militarised state we know of today. Homosexuality among men and boys was mandatory. The training of Spartan youths is explained, from their enrollment in the Agoge system right through to their attainment of citizenship. The class structure of the Lacedaemonian state (Helots, Perioeci, and the soldier-citizens themselves) is also covered. The episode ends with the battle of Thermopylae, in which 300 Spartans, including their king, Leonidas, were killed in action defending Greece from a Persian invasion. Part 2 opens with the retreat of the Persians, after Thermopylae and the battle of Salamis. Athens, which had
Delian League to the Persian Empire, and Eretria was duly destroyed. However, the invasion ended in 490 BC with the decisive Athenian victory at the Battle of Marathon. Between the two invasions, Darius died, and responsibility for the war passed to his son Xerxes I. Xerxes then personally led a second Persian invasion of Greece in 480 BC, taking an enormous (although oft-exaggerated) army and navy to Greece. Those Greeks who chose to resist (the 'Allies') were defeated in the twin simultaneous battles of Thermopylae on land and Artemisium at sea. All of Greece except the Peloponnesus thus having fallen into Persian