At the end of the movie, when Leonidas knows he is going to die, he tells Dilios to go back and tell everybody what happened. He also takes some sort of braid or string out of the back of his hair and tells Dilios to give it to Queen Gorgo, which Dilios does. Queen Gorgo then puts it around her son's neck as a necklace. Does anyone who knows something about ancient Spartan culture to know what the significance of this item was? Also, why was Leonidas wearing it as a braid, while his son wears it as a necklace?
I'm going to attribute it to the most powerful force in the universe -- Plot. It's a way to represent communication between Leonidas and Gorgo as well as a mechanism to 'pass the baton' to his son.
I shall further speculate that it was worn as a braid rather than a necklace so as not to interfere with visual of a ripped and oily Gerard Butler jumping and slashing all about.
While it would be awesome if it were some sort of manifestation of a Spartan ritual, the movie (even more so than the graphic novel) is so far afield from actual Spartan history, it's a surprise they still called them Spartans.
He knew he was going to die and didn't know how to tell her goodbye, it even says in the movie "what should I tell her?" "nothing that need be said" and Spartans aren't supposed to show weakness so that was their way of telling each other they loved each other and in the end maybe she just wanted to pass something on to their son from his father.
IIRC the neckalace his wife hands him is actually a claw or fang from the creature that Leonidas kills in the beginning of the film. I think he gave it to his wife to show his prowess as hunter/fighter. She in return gave it to him to remind him of this feat as an encouragement to return as a victor.
I don't think any of these quite nail it, and it is kind of an awesome plot point.
Part of the Spartan culture, that was somewhat addressed in the movie, was the concept of "come back with your shield or on it". Meaning comeback with your shield or dead, but not alive without your shield. (Doing so would signify desertion.) A shield often doubled as a stretcher. The shield has significance culturally as it protected your fellow soldier in the phalanx formation, and by the transitive property thereby protected the city state and your loved ones.
If you recall Ephialtes was rejected solely for his inability to hold a shield at the proper height.
By sending back the necklace he communicated many things:
- I am going to die, but will do so bravely
- Goodbye my love
- You won't see my body again
- It's time for a new king
- It's time for our son to be the head of the family