Sparta was a powerful city-state in ancient Greece. The Spartans spoke Greek. They thought of themselves as Greeks. Like all Greeks, they would identify themselves as being from their city-state, in this case Sparta. But Sparta was very different from the other Greek city-states.
You may have read on the web that Sparta had two kings. That is true, but it is only part of how Sparta ran their government. Power was concentrated in a Senate composed of a small group of 30 retired warriors. The Senate ruled Sparta in times of peace. Sparta also had lifetime co-rulers of two kings, whose job was to arbitrate in times of war. This type of government is called an oligarchy, or rule by a small group. There are different kinds of oligarchies, such as wealth, birthright, military. Sparta was a military oligarchy. Sparta actually had a constitution that clearly defined and dictated how government in Sparta was to operate. It was a rigid oligarchic constitution and it was in place and followed by Sparta for many hundreds of years. That system was unique. Most Greek city-states were ruled by a king. Athens had a system of direct democracy of sorts for 100 years, but for the rest of their ancient existence of over a millennium, Athens was ruled by a king.
All citizens in ancient Greece were warriors. But the Spartans were the best warriors of all of the city-states. The Greeks argued about many things, but there was no argument about that. The city-state of Sparta was basically a well-trained army. In other city-states, children entered military school at age 18. In Sparta, they entered at age 6. The girls were taught how to fight as well. Their school was separate from the boys' school. It was not as brutal, perhaps. But still, the girls learned how to fight and steal and lie and kill - skills that could save their lives in times of war.
The Spartans were tough.
Men and male children, from the age of 6, lived in the soldiers' barracks until they retired from military service. They visited their families, but they did not live there. The men were often off fighting. The women were left behind to guard their homes. Perhaps because of this, women in ancient Sparta had a great deal of freedom. They ran businesses. They were free to move around and visit neighbors without asking their husbands permission, even when their husbands were not off fighting.
But not everyone who lived in Sparta was a citizen of Sparta. To be a citizen with full rights, the men had to pay to prove they were the ancestors of the original people who lived in Sparta. If they couldn't prove it, or couldn't afford to pay for the search, they were not citizens. Citizens had many rights like the right to a fair trial and the right to be educated to be a good warrior and to live in the barracks. Non-citizens could be killed for no reason at all. Non-citizens had few rights, although non-citizens could own and operate businesses. It was a very strange system. It was uniquely Spartan.
The other Greek city-states had no desire to be Spartans. Many thought they were military fanatics, but they admired their strength. Greek city-states did team up against each other on occasion. Spartans were good friends to have in times of war.
No incredible works of art were created in Sparta as they were in other Greek city-states. Their focus was on war and preparation for war. But they did not go to war simply to go to war. They tried, if possible, to arbitrate and settle their differences peacefully with other Greek city-states when they were in disagreement. They even tried to solve things peacefully with other civilizations around the Mediterranean who attempted to intrude upon their lives. When they could not, they went to war.