King Leonidas and Queen Gorgo of Sparta

In Sparta, one's forbidden lineage was through one's mother. Half-siblings who only shared a father were allowed to marry. Surprisingly, despite the fame of King Leonidas through 300, most people don't realize that Gorgo was the daughter of Leonidas' half-brother, the previous king. Indeed, Leonidas was himself the result of an uncle-niece marriage.

Spartan bust of King Leonidas

 

Gorgo was known for her independence and wisdom even in her youth, when she advised her father not to aid a rebellion of Anatolian Greeks against the Persian Empire. Considering how incredibly sexist the northern Greeks in Athens, Corinth, etc. were, the story about her circulated because it shocked them.

[...] [A]t about the age of [eighteen or nineteen] years old, she advised her father Cleomenes not to trust [...] a foreign diplomat trying to induce Cleomenes to support an Ionian revolt against Persians. "Father, you had better have this man go away, or the stranger will corrupt you." Cleomenes followed her advice. 

Spartan women were notorious for their independence and intelligence, and given that Gorgo traveled with Leonidas frequently, the rest of Greece had plenty of opportunity to see that in action.

Gorgo was the kind of woman abhorred in the rest of the Greek world – a woman with her own opinion and the audacity to voice it in public. [...] [H]er most famous quote was in answer to an Athenian woman who wanted to know "why only Spartan women rule their men."  Gorgo replied: "Because only Spartan women make men.".

Spartan bust of Queen Gorgo

The thought of Gorgo in Athens is rather like that of the Connecticut Yankee in King Arthur's court. She must have been a sensation – and one imagines Leonidas, with his dry sense of humor, enjoying every minute of it! For example, note that the Athenian woman asked why only Spartan women "ruled" their men, implying that Gorgo had been seen giving Leonidas advice – and he had been seen to accept it, just as Cleomenes had done before him.

Regardless of his famous death in battle at Thermopylae, during his life Leonidas was better known as a statesman. He spent his entire reign rallying support from all the Greek cities to form a military union against Persia. He also demonstrated a very Spartan distaste for self-aggrandizement and the hunger for personal power.

When the Persian emperor Xerxes offered to make him king of all Greece, he replied: "If you understood what was honorable in life, you would avoid lusting after what belongs to others. For me it is better to die for Greece than be monarch of my nation."

Also, Leonidas wasn't brave to the point of suicide. He didn't stand and fight at Thermopylae against impossible odds out of some blind sense of heroism. He did it because he believed the gods demanded he give his life in exchange for Sparta's safety. So said the Delphic oracle.

But Leonidas had a double burden. On the one hand he was elected by the allies to organize and command an effective defense against the Persians, and on the other hand he had been warned by the Oracle of Delphi [...] that:

Listen, O Spartans of the open plains:
Either Xerxes will sack your gracious town
And place your women and children in chains,
Or you will mourn a king of great renown.

There is one quote, however, that truly demonstrates what kind of person he was, and what kind of relationship he and Gorgo had.

When Leonidas marched out to die at Thermopylae, Gorgo asked him for instructions. His answer was a final compliment to her. He said: "Marry a good man and have good children." Not sons, children.  Leonidas wanted Gorgo not to mourn him but to be happy, and he valued daughters as much as sons – probably because he had learned from Gorgo the importance of clever and loyal women.

On a side note, Sparta was nothing like it's commonly depicted. (Surprise, surprise! 300 isn't historically accurate!) I won't go as far as to say that conventional wisdom on Sparta all comes from propagandistic Athenian historians, but I wouldn't be that wrong if I did. Notice how in all the busts, including of Leonidas, they're smiling? It was conventional in Spartan sculpture to depict people smiling, and in fact Sparta had monuments to Gelos, the god of laughter.

The early Spartans (before their decline and downfall) were known for their public schools (for both sexes), their devotion to the law and the community, their poetry, their music, their dance, their philosophy, and their fierce women, not just their military prowess. Their terse wit was so honed that Spartan sayings were commonly repeated throughout Greece. They had an elected council and a public assembly generations before Athens was democratic. Spartan women were also more involved in the economy than Spartan men, since the men were usually fighting or running the affairs of state.