For centuries before - and after - the first Persian invasion at Marathon, ancient Greece was not a united country. Cities were states unto themselves, each with their own government. Sometimes the cities helped each other; sometimes they fought each other.
To avenge his father's loss at Marathon, Xerxes formed an army with men from many different countries. All part of his empire, the united invasion force even included subjected Greeks. One Greek - Demaratus - was formerly a king of Sparta. He would play a key role as Xerxes’ advisor.
Where was ancient Sparta? What was life like there? Why would her former king advise the enemy? Located on the Peloponnesian Peninsula, the city - and its people - have an interesting history.
At the time of our story, Sparta was known as Lacedaemon. Both names are rooted in Greek mythology. Lacedaemon, son of the chief god Zeus, was married to Sparta. Naming the country he ruled after himself, Lacedaemon called his capital city Sparta, after his wife.
Mountains - including Mt. Taygetus - protect Sparta on three sides. Nearly thirty miles from Gythium - its port - ancient Sparta was not easy to blockade.
Unique among the Greek city-states, Sparta had her own standing army. It commanded authority over nearly 4,000 square miles. To signify they were Lacedaemonians, Spartans used the Greek letter lambda - Λ - on their shields. Spartans believed their kings - they had two who ruled together - were direct descendants of the great hero Herakles (later known, by Romans, as Hercules).
Sparta’s education system focused on physical ability and military prowess. Even girls took part in physical activities. A surviving bronze sculpture, likely created in (or near) Sparta, depicts a young girl running.
Paul Cartledge, in Thermopylae: The Battle That Changed the World, describes Sparta’s unique society and culture at the time Xerxes was amassing his army:
Professionals in a world of amateurs, the Spartans alone of Greek cities maintained a standing army. But they were not militaristic in the sense that they enjoyed war for its own sake. That unique army was invented and maintained, first and often foremost, to dominate and suppress the Helots [the Spartan slaves]. In fact, their whole society was organized as a kind of standing army. It was kept ever on the alert against the enemy within, as well as against any Greek or non-Greek enemies from without. (Cartledge, page 65)
It was from such a place that Leonidas - one of Sparta’s kings - would soon inspire his men to stand firm, and fearless, against Xerxes and the Persian army.