It would need a book, probably in three volumes, to even begin to do justice to Sparta. The place was like nowhere else we know of, before or since. Spartan life was so removed from our modern experience, that it would almost be reasonable to say that while Athens strove to become us, Sparta was determined to be the exact opposite. It's no wonder the Athenians and the Spartans could never trust each other.
I won't try and write a book; instead I'll point out a few of the weirder parts of Spartan life:
They called themselves Lacedaemonians, from Lacedaemonia. Try saying that ten times fast. Which is why you typically see the letter lambda on their shields.
Sparta had two kings, running in two ancient lineages. Presumably this was a carryover from when the city formed from multiple tribes. It did mean that a new, inexperienced king could be balanced by one with more experience. It also meant a certain amount of argument!
Each newborn baby boy was taken by his father to a committee, which decided whether the child was fit to live. If not, then the baby was exposed to die, by order of the state committee. But if, much more usually, he was fit to live, then the baby was allocated on the spot a plot of farmland which was his for life: his source of income and support. The plot came with helots to work the land; all the owner had to do was eat the produce. When a man died, his farm was returned to the state for allocation to the next baby that came along. It's hard to know what to call this by modern standards. Fascism? Communism? Beats me.
There was only one profession for a Spartan: to be a soldier. The other two classes were the helots—who were slaves—and a small band of free non-citizens called the periocoi.
Helots were a once-free people who were made slaves by the Spartans. The helots rose up on a semi-regular basis. Which is why the Spartans were dedicated soldiers: not to fight wars but to keep the helots in line.
Helots were not slaves in the normal sense that they could be bought and sold at will. They were tied to the land. In some ways they were more like serfs than slaves.
There was a rite of passage for young Spartans called the krypteia, in which the young men were sent alone into the countryside, with only a dagger, and orders to survive without being caught. Oh, and each young man was to kill a few helots. For practice, you know. It was a way of getting the young men used to killing before they had to do it much more dangerously in combat, and it seems as if helot troublemakers were particularly targeted, thus killing two birds with one stone, so to speak.
When a man came of age he was allocated to a mess, which also formed his fighting unit. He stayed in that mess for life.
Spartan women, surprisingly, were the most free of any of the Greeks. The theory went you needed women in good condition to produce strong children.
There was a council of elders, called the gerousia. Membership by invitation only, and you had to be 60 years or older (gerousia...geriatric). Any Spartan who lived to 60, considering the battles, had to be one tough guy.
5 ephors were selected each year from amongst the Spartiates. The ephors held veto power. Whenever a king left Sparta, 2 ephors would accompany him. Any 2 ephors together ccould overrule a king. All 5 ephors could overrule both kings. Ephors were rather powerful.
The first action of the newly elected ephors each year was to declare war on their own helots. So it was legal to kill them without fear of blood guilt, you know.
It was illegal to have a funeral stone unless you died in battle.
For a Spartan to surrender was the greatest shame. In fact to fail to die in battle with your comrades was pretty bad too. There was a man sent off on an embassy by King Leonidas, right before the last stand at Thermopylae. When this man discovered that he'd failed to be slaughtered along with his friends, he was so ashamed he hung himself. A small force of Spartans surrendered to the Athenians during the Peloponnesian War. All of Greece was shocked.
Sparta was structured like four connected villages, each with its own agora. It probably means Sparta coalesced in prehistoric times from four tribes. Unlike every other important city in Greece, Sparta had no defensive walls. The Spartans took the view that anyone who thought they could beat them was welcome to come on in and try.
The Spartans were totally convinced this new-fangled money stuff would never catch on. Instead, they used small iron bars for the few times currency was needed in their lives. Even a couple of hundred years after coinage was invented, the Spartans were still resisting.
The Spartans did from time to time hold general votes. How they voted was this: some men were sent outside the assembly hall. The Aye voters and the Noe voters then shouted as loud as they could, one group after the other. Whichever side shouted loudest won the debate, as decided by the listeners outside.
They called themselves Lacedaemonians, from Lacedaemonia. Try saying that ten times fast. Which is why you typically see the letter lambda on their shields.
Spartans were sometimes referred to amongst other Greeks as "crickets", because they were always ready for a sing-song and communal dancing.
The Spartans were renowned as a people of few words. Our modern term laconic comes direct from Lacedaemon. So the next time you describe someone as laconic, you're accusing them of being like a Spartan.
I could go on forever, but I'll stop there. If people read of a place like this in an epic fantasy, they'd say it was over the top.