Historically, Plataea is a city-state in ancient Greece. It was the only polis to send soldiers to help Athens fight the Persians at the battle of Marathon; it sent about a thousand hoplites to join with the ten thousand men from Athens, to face four or five times that many in Darius’s Persian army. A decade later, Persia’s new king, Darius’s son Xerxes, sent an even larger army to invade and conquer Greece (perhaps as many as a quarter million strong), resulting in the famous Greek loss at Thermopylae and the victory at Salamis. The following year, it was at the Battle of Plataea that the remains of Xerxes’ army was defeated.
In this future universe, Plataea is a planet in the TBD system. It was a terraforming success, and is run by a fairly libertarian minimalist government. Voting rights are earned, and there are a number of ways to earn them. There are NO forms of “public assistance,” it’s all privately run and family supported. It isn’t a military-centered world, but there is a strong streak of “peace through strength.” One of their main “exports” are small groups of mercenaries. As a rule, they don’t fight for the richest offerings, but for the side doing the fewest stupid things economically and legally.