This is nothing more than another Hollywood carton. Leonidas himself would probably turn in his grave if he ever to see the depiction of himself, his country man and Sparta in such way.
Creators either had no knowledge or no respect for actual history and the character of the actual people who participated in those events.
The only things they got right (a) there was a battle at Thermopile against Persians, (b) all 300 Spartans that were there were killed , (c) the Spartans and allays were lead by Spartan King Leonidas, (d) Persian King's name was Xerxis, (d) Leonidas did have a wife and a son. That’s about it. Everything else is absolutely ludicrous.
Here are some of the most ridiculous aspects of the movie:
(a) Leonidas kicking emissaries into the well - RIDICULOUS! The emissaries were thrown into the well, but it could hardly could have been Leonidas, as he was known as a phenomenal diplomat. I think this was even before he became King, and Persian King wasn't Xerxis, but his father. Killing emissaries was not only unthinkable for any nation considering itself civilized, it was also considered an offense to the Gods. He would never ever do that.
The Spartans later were so ashamed of that act and terrified of the consequences with the Gods, that they actually have sent 2 volunteers to Persian King to give away their lives as a sacrifice to make up for those killed ambassadors.
(b) What in heck Xerxis wearing???? What's with that insane looking S&M outfit of chains and gold thong???? He is a King of Persia - the richest and most powerful empire at the time. Persians were known for the magnificent hair and beards that they braided and decorated and for dressing themselves in most magnificent silk robes imaginable!! Layers and layers of silks!
(c) The way Spartans are dressed is almost equally ludicrous. Greeks, and Spartans in particular, were known for fighting in phalanx which form a WALL OF BRONZE. They had MASSIVE shields that were covering them from mid-shins to shoulder, helmets covering face completely, breast plates and greaves. Yet in the movie they all dance around and jump like in a ballet in some silly leather bikinis and red capes. Just stupid.
As far as the red cape in which they run around in the movie - it wasn't really a cape, it was one of those greek things people used to wrap around themselves in. And it was only used if it was cold, no one would be fighting in it of course, as it'd be tripping people over, etc.
(d) Fighting - absolutely ridiculous in the movie. If you put on all that gear I described above and factor in that shield was bronze on the outside while oak on the insides - you can get the idea how freaking heavy all that was. You are not going to jump around like a ballet leading figure in that kind of armor.
The fighting in fact was so exhausting due to heat and overwhelming number of men they were killing, no one was jumping, people were beyond exhausted and driven by honor and determinism, working in their formations, which Spartans were known for.
(c) Lastly, I don't remember if they shown that in the movie or not, but 300 Spartans meant - 300 Spartiate citizens + 300 attendants (at least 1 for each Spartite) + tons of other personnel (semi-slaves) who were in charge of provisions, etc. In additional to Spartans there were a number of other Greek troops. And even at the very end when Leonidas ordered them all to go to save their lives, 7,000 men from Thespie stayed and fought with them till every last one was dead.
Few other interesting facts - Leonidas at the time of the battle was between 50 and 60 years old. Most historians think he was closer to 60. The actor in the movie is quite young.
Spartans were known for wearing their hair long and braiding them. Only young spartans had it shorter, as you were only allowed to start growing it after 21 years old.
Leonidas was in fact an absolutely remarkable figure. There is so much historical data on what a remarkable and inspirational person he was. The movie shows his as a brute in leather bikini. Such a shame.